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TRANSCRIPT
Running Head: LEARNING TRAJECTORIES
Learning Trajectories, Learning Progressions, and Hypothetical Learning Trajectories
Kimberly Morrow-Leong
Analysis for Portfolio #3
August 2014
George Mason University
LEARNING TRAJECTORIES
Teachers’ in-the-moment decisions and resulting actions are key factors in the
advancement of the student learning. A classic article in a teacher practitioner journal
entitled “Isn’t that Interesting!” Buschman (2005) describes a teacher’s intentional decision
to step away from judging student responses and ask questions about their thinking
instead. The anecdotes from the classroom demonstrate the broad range of
misunderstandings, pre-understandings, and exceptionally diverse thoughts that students
share when their line of thinking is pursued. On the other hand, I reviewed a study guide
that outlined a professional development activity centered on this article (not in print).
The study guide author apparently misunderstood the author’s intent, as the professional
development guide focused on teachers’ strategies to help students correct their
misconceptions. Not all teachers have a habit of listening carefully to what students are
saying and using this information to assess their thinking.
Students’ growth and development can take surprising twists and turns, sometimes
following the curriculum set for them and at other times meandering around important
ideas without achieving the objective of the day, week, or even of the year. Nevertheless,
teachers still hold the key to guiding students toward a more robust understanding of
mathematics. With the introduction of the Common Core State Standards (2010) a close
examination of learning paths may be more feasible, as much of the population is following
the same curricular sequence. However, a sequence of content presented by grade is no
guarantee that each level of content is appropriate for the students in that grade to learn.
Much research is needed in order to conclude definitively that, for example, the division of
fractions in 6th grade is appropriately accessible for every student in the United States. In
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the meantime, learning trajectories and progressions may become key tools for assisting
teachers as they learn more details about the means by which mathematics students learn.
Search of the Literature
In this paper I will review the history of research on curricular sequences such as
learning trajectories and learning progressions in mathematics education and conclude
with definitions that will show how each is valuable in its own contexts. Furthermore, I
will also describe learning progressions and learning trajectories in specific domains in
order to not only summarize some of the important known information, but also to
compare and contrast the LT and the LP when used in practice. Finally, I will present
reflections and recommendations for further areas of research and advice for practicing
teachers for using these tools.
To begin the search, I entered the following search terms in the Academic Search
Complete database: “learning trajectory(ies)” and “learning progression(s),” initially
specifying “mathematics” in the search. This yielded several hundred entries, which I
narrowed down by sorting chronologically. After scanning the first few dozen most recent
articles, I downloaded those that appeared relevant to the search topic. For the second
phase of my search, I looked up what I knew to be the seminal article (Simon, 1995) and
selected the link that led to all articles that cited that piece. When this yielded a large group
of articles, I narrowed the search to articles within the field of mathematics only. The
combined collection of articles was sorted into groups, as I was attempting to identify
research teams that were working on different trajectory projects. This phase of the search
yielded six or seven teams of researchers working on projects focused in different
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mathematical domains. It also yielded a collection of published pieces that hinted at
individual research projects that utilize the frameworks designed by other teams. For
example, one article describes a study that contrasted the use of learning trajectories in the
lesson planning process by veteran and early career teachers (Amador & Lamberg, 2013).
Finally, after examining the evolution of the learning trajectory and the learning
progression within the field of mathematics, Batttista (2004) and others referred back to a
document published in reference to science education learning progressions (Corcoran,
Mosher, & Rognat; 2003).
Sequences provided for teaching within content area domains is not a uniquely modern
phenomenon: any teaching or training activity must include some form of a plan that leads
students from ignorance to a mature understanding of the domain content and skills. Lave
(2011) describes the process as apprentice tailors enter the community of practice
(Wenger, 1998) and begin to engage. The strict sequence of mastery skills and assessment
routines followed by the male tailors within the Vai and Gola community of Liberia are
notable. The sequence of skills that are learned on the periphery include sewing on a
button, but eventually move to full participation when the apprentice earns the
opportunity to tailor a suit. Students learning mathematics are also on an apprenticeship
path. The Common Core specifically identifies that path by stating that the goals of the
standards are “college and career readiness” (CCSSO, 2010). It is beyond the scope of this
paper to argue whether this is an appropriate set of standards and goals for every student
in the United States, or whether these standards truly do move students toward the stated
goals, however an understood set of goals, tasks, and a predictable sequence of expected
competencies guide the master’s efforts to mold the apprentice.
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Big Picture on Student Learning
The unfolding of topics and content that students learn in a classroom is not an obvious
sequence, and opinions about this progression vary greatly. One of the key considerations
for describing the sequence students follow is the focus and intent of the sequence. One of
the outcomes of the research done by Confrey and colleagues as part of the development of
the equi-partitioning learning trajectory is a clear distinction between a sequence of
content based on mathematical ideas that originate from an idealized version of
mathematics as an end goal, and a view of mathematics as something that is created within
the individual mind (Confrey, 2012; Wilson, Mojica, Confrey, 2013). In other words, a
mathematics learning sequence can be derived as a top-down model, where the content
that students must learn is derived from a vision of what mastery of that content looks like.
Because this vision of mathematical learning is conceived by those who have already
achieved mastery, the content looks much like the mature version. On the other hand, a
developmental view of mathematics learning builds from the earliest conceptions of
number and space and assumes that learning will unfold in fairly predictable ways, given
that students have exposure to productive mathematical tasks. In this view, student
thinking and learning unfolds in “stages” or “levels” that have been shown empirically to be
predictable. Of course these approaches are overly generalized, but it is useful to adopt a
critical stance when examining any curriculum, learning progression, sequence, or learning
trajectory and decide how the writers conceptualize mathematics learning. Sztain, Confrey,
Wilson, and Edgington (2009) base their work with learning trajectories on a
developmental view of mathematics and present evidence of empirically based movement
through a series of conceptual ideas related to rational numbers.
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Origins of Learning Trajectories
When Simon (1995) published this article he casually mentioned the hypothetical
learning trajectory. A careful reading shows that he may well have preferred that the
mathematics education community instead elect to study the model of the iterative
teaching decision-making process that he called the Mathematics Teaching Cycle. Beginning
with a reasonably educated guess about the interactions between a lesson’s goal, the
activities of the lesson, and the thinking and learning in which the student might engage,
the teacher lays out how a lesson might unfold: Simon called this part of the iterative
design cycle the hypothetical learning trajectory (HLT). The rest of the cycle is concerned
with the changes in lesson design both live in the class and also for future instruction. But
this is not what caught fire.
It is clear that Simon’s focus in 1995 was on the individual teacher’s work within a
single classroom, even within a short time frame. He specifically refers to “the teacher’s
prediction as to the path by which learning might proceed” (Simon, 1995, p.135). The HLT,
as an instructional planning tool has evolved considerably since this original statement.
The H has been dropped, and more definitive statements about the learning trajectory for
certain content domains have emerged. Others retain the H but have shifted the
hypothetical aspect to refer to a proposed global hypothesis about student learning within
a content domain, rather than to the context of a single teacher or classroom. Other entities
have adopted the term “learning progression,” distancing themselves from anything
remotely hypothetical. Few writers retain what I believe is Simon’s original meaning
within the context of this paper, including Simon himself (Simon and Tzur, 2004). In this
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piece, the authors present the HLT as a “vehicle” for instructional planning. The
importance of tasks and a focus on students’ understanding remain, but in this piece the H
seems less hypothetical. For example, the lesson shared in Simon’s original piece begins as
an exploration of the “multiplicative relationships involved, not to teach about area”
(emphasis in the original) (Simon, 1995, p. 123), but eventually he admits that “Although
my primary focus was on multiplicative relationships, not on area, it seemed clear that an
understanding of area was necessary in order for students to think about constituting the
quantity (area) an evaluating that quantity.” In this responsive shift in focus, the
hypothesized learning trajectory for the group of students changes significantly, even in
some sense shifting domain, and the hypothesis about the students’ learning path changes.
But in the 2004, Simon and Tzur (2004) use the word “vehicle” to describe the elaborated
hypothetical learning trajectory conveys the idea that the HLT “carries” the lesson instead
of driving it. The agency appears less in the hands of the teacher and is more dependent on
the sequence of activities designed to elicit activity-effect in students. Despite this subtle
but noticeable shift in emphasis from the teacher as the author of the HLT to a research-
determined HLT, the authors do acknowledge that as knowledge of student learning
processes grows, learning trajectories in general can become more precise and predictive
than they have been in the past. However the HLT, as originally presented, has evolved
significantly in the intervening years.
Currently, Confrey and her colleagues (Confrey et al., n.d.) have outlined learning
trajectories for all of the mathematical domains presented in the Common Core standards,
building on current empirical research on student learning, particularly in the area of
rational number understandings. They use the term “learning trajectory” in a definitive
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way. The LT is a “researcher-conjectured, empirically-supported description of the ordered
network of constructs a student encounters through instruction (i.e., activities, tasks, tools,
and forms of interaction), in order to move from informal ideas, through successive
refinements of representation, articulation, and reflection, towards increasingly complex
concepts over time” (Confrey, Nguyen, Mojica, & Meyers, 2009, p.347). Where the Common
Core omits intermediary standards they deem necessary, they have added “bridging
standards” to complete the connections (Maloney, 2013). In all cases, this LT is not an
individual teacher construction, but rather a compilation of extant research in the domain.
Like Confrey, Battista also excludes the “hypothetical” aspect of the learning trajectory
and illustrates in detail Simon’s distinction between the general case of a learning
trajectory and the actual case (Battista, 2011). In a series of case studies he describes
students’ acquisition of understanding of linear measurement progressing from the use of
non-numerical comparison to the abstraction of length, apart from iterated units. Using a
mountain analogy, he illustrates a student’s idealized path up the mountain as an efficient,
but not necessarily direct, path through the big ideas and concepts that characterize
progress toward a sophisticated understanding of linear measurement. This is the
prototypical trajectory. He also presents the more typical, or actual, learning trajectory
that meanders between levels and sublevels, often doubling back and retracing steps.
Altogether the actual learning trajectory could be far more disjoint than one might expect.
A fifth grader’s particularly complex progression through a collection of 34 measurement
tasks is illustrated in Figure 1. Beginning with an accurate but non-numerical comparison
of lengths on level N1, the student’s path through five other levels of thinking seems to
settle in M1, showing that he is most likely to incorrectly iterate lengths of units. This
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actual trajectory is admittedly more complex than most children’s. It does, however,
illustrate that the nature of a learning trajectory is different when applied to a student’s
particular case, a particular class’ case, than when it refers to the general case.
Figure 1: RC's learning trajectory
Battista’s conception of learning trajectories broadened and extended Simon’s original
ideas. While Simon’s original description referred to the teacher’s individual process of
preparing for instruction by anticipating how students will respond to tasks, Battista’s, and
indeed Simon and Tzur’s more recent work as well (Simon, 2014), lays out a empirically
informed prediction of how students will respond to different tasks. Perhaps it is
inevitable that a continued focus on student thinking and a cataloging of their responses to
typical assessment items will yield “prototypical” results that can be sequenced and
mapped. The difference here is agency. Whereas the original conception of the HLT
included the teacher’s routine reflection, planning, and response to student thinking and
learning, which is a model more akin to a constructivist orientation (von Glasersfeld, 1995),
the elimination of the “hypothetical” aspect in practice lessens teacher agency.
This is not the case across the board. Gravemeijer (2003) still holds the teacher in the
instructional designer role, adhering to a design research brand of planning for teaching
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that expects the teacher to imagine the path students will take during a lesson. Moreover,
Smith and Stein (2011) also include an expectation that teachers will include an
anticipation phase in the lesson planning process. They define anticipation as “actively
envisioning how students might mathematically approach the instructional task” (Stein &
Smith, 2011, p.8). However, they make no mention of the source of information that
teachers might draw upon for their anticipation work. Finally, Ellis, Weber, & Lockwood
(2014) acknowledge the challenges involved in planning instruction that is responsive to
students’ anticipated approaches to tasks. In their review of the literature related to
learning trajectories and learning progressions they conclude by stating that the most
honest reality is that attending to student thinking and building their own interpretations
of student learning trajectories are skills rightfully acquired over time. Teachers’
anticipation of students’ thinking and learning processes is clearly of utmost importance,
however teacher agency does not necessarily form a part of all theoretical frameworks
related to learning trajectories.
The Nature of Learning Trajectory Paths
Linear Paths
The Oxford dictionary defines a trajectory as “the path followed by a projectile flying or
an object moving under the action of given forces” (OED, 1914). If we adopt the trajectory
as a metaphor for learning, it’s important to consider the shape of the learning paths as
well as the forces that influence movement along the path. Figure 2 shows five possible
conceptualizations of the learning trajectory phenomenon. In the linear model, learning
follows a straight path, unmarred by detours or complexities. Gagné’s (1977) Task
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Analysis model is typical of this learning path. The Task Analysis model begins at the end
of the learning process and identifies the goal of the task and then the most desirable
sequence of learning events. The task is then classified by the kind of activity that best
demonstrates student success, and the designer then maps out a detailed path to achieve
this goal. One of the necessary steps in the process is the establishment of prerequisite
knowledge, which are all of the skills that must be in place in order for the student to move
forward toward the target goal. Prerequisite knowledge is a concept well-known in the
tradition of lesson planning, as it is an important piece of establishing a starting point for
instruction. In reality, the Task Analysis model is more accurately called an instructional
design model rather than a model of learning because the design describes strategies that
can be used to guide student learning, but it does not describe actual student learning in
any fashion.
Linear Meandering MultipleLandscape/
NetworkBranching
Figure 2: Learning Trajectory Paths
It is important to review the work of Gagne in the discussion of learning trajectories
and learning progressions, because many of the constructs proposed by Gagne are contrary
to the nature of what a learning trajectory is. Gagne’s Task Analysis model is linear, and it is
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certainly a “top-down” model of instruction in that the instructor begins with the end
target knowledge goal in mind and then scrutinizes the incremental steps that lead up to
that goal, developing a carefully constructed sequence of tasks and skills that lead directly
to the end goal. By contrast, the learning trajectory. as well as the hypothetical learning
trajectory, all begin with the learners’ most immature understandings and charts the
progression of learning toward a mature understanding. In a later section, we will explore
the subtle differences between the learning trajectory model and the learning progression.
Origins
Recently Simon (2014) outlined his most current iteration of the HLT theory supporting
a task design process for teaching skills and concepts that are not readily learned in the
problem solving context. He specifically separates this form of teaching from a problem
solving approach and has only employed these task sequences within the context of a
teaching experiment. During the teaching experiment, the interviewer elicits a student’s
responses to tasks for which the student already has some facility. The subtly sequenced
and crafted tasks allow students to move toward reflective abstraction, a state which
allows them to complete a task without the accompanying physical action. At that point the
student has constructed enough understanding to complete the task without intervening
steps. The task sequences employed in this line of research are very carefully constructed
and based on the painstakingly detailed sequence of fraction schemes outlined by Steffe
and colleagues (Steffe & Olive, 2010).
Steffe and his colleagues do not use the term “learning trajectory” when discussing their
teaching experiment results, most likely because their work is not designed for classroom
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use, and the learning trajectory specifically includes the instructional task component.
Nevertheless, minus the real classroom tasks, this group has generated a highly detailed,
linear, and fine grained description of how a typical student will progress through their
understanding of rational numbers. One key component of the overall theory is the
reorganization principle. As students demonstrate incremental changes in the
instructional tasks with which they engage, they assimilate the new information (Piaget &
Inhelder, 1973) and reorganize their current undrestandings. In this minute manner, Steffe
and Olive hold that students will not be subjected to interference from the natural number
operations: the tasks are designed to subtly but surely extend the students’ understanding
of natural numbers to include the set of non-natural rational numbers (Steffe & Olive,
2010). The fraction schemes they outline are detailed and specific, including arcane
acronyms for fraction schemes that are not only anticipated and predicted, but which also
follow each other in a nearly universal order.
Despite the fact that the term learning trajectory is not used to describe the fraction
scheme, the sequence still retains some of those properties in that they present a projected
and expected sequence of concepts that will elicit disequilibrium in students. As these
states of disequilibrium are anticipated, instructional tasks are already prepared that are
ideally suited to assist students to move toward assimilation of the new ideas. For
example, Norton and Wilkins (Norton & Wilkins, 2010, 2012) conducted detailed teaching
experiments with seventh grade students in order to determine the most accurate model
for students’ acquisition of the fraction scheme. For example, a student who possesses the
partitive unit fraction scheme (PUFS) can partition a continuous whole into n number of
parts, such as a stick partitioned into 8 equal pieces. But the PUFS scheme also means that
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the student can remove one piece, iterate it back against the unit whole and name the
corresponding unit fraction (1/8). PFS, the scheme hypothesized to follow the PUFS
includes the understandings required for the child to have acquired PUFS. The significant
difference is the students’ capacity to recognize fractions besides the unit fraction (1/8),
and reconstitute the unit whole. Using the 1/8 example, the student would recognize 3/8
as three iterations of 1/8 and then reconstitute the 8/8 or 1 whole. This change to more
multiplicative thinking also permits the students to make sense of the improper fraction.
9/8 is no longer perceived as “nine parts out of eight,” but rather as nine iterations of 1/8,
which itself is one out of eight partitions of the unit whole. While this scheme still retains
additive properties, it is an example of how Steffe envisioned an understanding of fractions
that is not in conflict with whole number operations, but rather part of a continuous
growth in understanding of number. And while not strictly a learning trajectory, the
schemes named and researched by Steffe and colleagues (Wilkins & Norton (2010),
Hackenberg, 2007; Olive & Steff, 2002) still retain the property of an assessable, and
imminently teachable set of touchpoint achievements and teaching tasks that are extremely
linear in nature. Simon, in his own teaching experiments is using this sequence of schemes
to formulate an HLT that can eventually be teachable (Simon, 2014). The combination of
expected student acquisition of mathematical knowledge combined with the instructional
tasks that are highly linear, put the combined work of Steffe and Simon in the category of
the linear trajectory.
The van Hiele levels of geometric thinking are certainly linear in nature (van Hiele,
2004). In order to see the linearity, it is useful to outline the nature of each of the levels
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and explore how the language of understanding and the mathematical point of view do not
just describe the students operating at that level, but also define their actions at that level.
Students at level 0 focus on the overall vision of a geometric figure, which Clements
refers to as a “Gestalt-like” view (Clements, 2004). The students’ language at this stage may
sound like they understand. For example, the student may be able to count four sides to a
square and tell you that it has four sides, but not recognize this property as a defining
property of a square. A less knowledgeable teacher will be satisfied at the depth of the
student’s knowledge, but not see the student’s immature thinking. At Level 1 the student is
mindful of the properties belonging to the geometric figure. They respond to verbal
indications of properties that may not be present in the actual figural representation. A
circle is a circle because all radii are the same length, and they will accept its “circle-ness” if
given this property. This is distinctly different from level 1, where the student would
accept equal radii as an interesting, but non-essential piece of information. At Level 2 this
detail is salient to the student. Level 2 is the beginning of mastery over definitions of
geometric figures, and at Level 3 the student is fully able to engage in abstract deductive
reasoning.
The van Hiele levels of geometric thinking are imminently satisfying, as they appear
discrete, understandable, and reflect situations common to all mathematics teachers. A
teacher may wonder about the “levels” of understanding inherent to other mathematical
domains which can help them interpret the mathematical understandings of their students.
There are criticisms of the van Hiele levels, particularly Battista’s critique of the absolute
nature of the levels, which imply that when students achieve that level they are at that level
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for all figures in all cases (Battista, 2011). Battista found that this is generally not the case,
in that student thinking may embody more than one level at a time depending on the task
at hand. His group has even gone so far as to identify percentages, as in 25% at Level 1,
58% at Level 2, etc.
Meandering Path
The meandering trajectory is best represented by Battista’s descriptions of the learning
progression for which he borrows inspiration from both Simon (1995) and the CPRE
science learning progressions document (Corcoran, Mosher, & Rogat; 2003). While the
CPRE document refers only to the learning progression, Battista clearly makes the case that
the learning progression in science is equivalent to the learning trajectory in mathematics.
While in mathematics “learning progression” refers solely to the development of students’
understandings of ideas, the learning trajectory also specifies the instructional activities
and expected student thinking that results from engaging in the activities. Battista’s
distinction between the LT and the LP is not universal and the differences on a more global
scale will be addressed again in a later section. What is important to recall is Battista’s
mountainside model for mathematics learning. The student’s learning path up to the
mathematical goal is not straight, but it is direct. Of course this is the average path for a
class, or a population, but in this model instruction follows the same approximate path.
The reality in the classroom looks more like the Multiple or branching path illustration.
Landscape or Network Path
The learning trajectory descriptions summarized so far are all distinctly linear, even if
the path meanders or if students travel along different paths. Fosnot and Dolk (2002)
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describe their work analyzing students’ strategies, schematizing, their big ideas, as well as
their modeling processes. They pointedly reject the linear model (learning line) because in
their view, it is much too linear to represent children’s learning processing. Instead they
adopt the landscape analogy for student learning, and put the teacher’s focus on the
horizon, which is the targeted mathematical learning goal. Assisting students as they make
their individual journey through the landscape of the domain is the teacher’s role. Fosnot
and Dolk, however, present their model of teaching within this broad and varied landscape:
their landscape is not specifically about the unfolding of student learning other than to
acknowledge that children will travel on different paths. In this sense, they are not
discussing a learning trajectory, however the landscape/networking analogy is still apt.
Confrey and colleagues’ definition of a learning trajectory is “a researcher-conjectured,
empirically-supported description of the ordered network of constructs a student
encounters through instruction (i.e., activities, tasks, tools, forms of interaction and
methods of evaluation), in order to move from informal ideas, through successive
refinements of representation, articulation, and reflection, towards increasingly complex
concepts over time” (Wilson, Mojica, & Confrey, 2013). The idea of an “ordered network of
constructs” recalls the landscape that Fosnot and Dolk describe in their series of
practitioner text resources (Fosnot & Dolk, 2002). The inclusion of “activities, tools, and
forms of interaction” in the above definition is also consistent with Simon’s inclusion of
instructional tasks in his introduction of the learning trajectory. The work of the
turnonccmath.net program, developed by Confrey’s research team (Confrey, et al. n.d.), has
produced a model of eighteen learning trajectories organized into a series of tessellating
hexagonal paths that reveal the details of the trajectories (see figure 3). Based on the
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Common Core standards, the turnonccmath.net trajectories attempt to meld the current
standards with the empirically supported understandings about student learning
(trajectories). When the standards do not correspond directly with the known trajectories
of student learning, the research team has created “bridging” standards that complete the
sequence of understandings. Interestingly, many of these bridging standards are part of
the body of research about student learning that were either left implied in the Common
Core or have been established since the publication of the CCSS. For example, the following
bridging standard connects 6.RP.1 to 6.RP.2 (CCSSO, 2010), elaborating on the big idea of
the unit ratio, a prominent idea in the 6th grade standards:
6.RP.1 Understand the concept of a ratio and use ratio language to describe a
ratio relationship between two quantities.
6.RPP.B Understand the concepts of ratio unit and unit ratio. Relate these concepts
for a given table of values and show them on a graph.
6.RP.3.b Solve unit rate problems including those involving unit pricing and
constant speed.
While standard 6.RP.1 introduces ratio as a relationship between two quantities, standard
6.RP.3 requires that students solve a full range of unit rate problems. One of the bridging
standards connects the ratio concept to the problem solving aspect by including the use of
both the ratio unit and the unit rate. The unit rate is any ratio relationship that includes a
unit of one as one of the values, and is a key focus in the CCSS. Recognizing that these unit
ratios are reciprocals of each other helps students increase their flexibility with the unit
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ratio. On the other hand, the ratio unit is the ratio that includes the least possible whole
number value for both numbers in the ratio. For example, 3/2 : 10 has a unit ratio of 3 : 20.
The bridging standard in this instance elaborates on a big idea, parsing out the key
mathematical ideas that are inherent to mastery in the next standard. While many of the
bridging standards represent key understandings, in some cases the bridging standards
that Confrey’s research team presents are essentially elaborations on strategies and
representations. Another of the bridging standards between 6.RP.1 and 6.RP.3 indicates
that students should be able to use a ratio table and a graph to show the relationship
between co-varying quantities. While there is little dispute over the validity of using and
connecting multiple representations, the use of such strategies is not necessarily a
standard.
Figure 3: turnonccmath.net
Branching
I have included the branching form of learning trajectory as separate from the
network/landscape model primarily because Baroody’s use of the term to describe his
conception of the student learning trajectory differs from others’ in substantive ways
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(Baroody, 2011). While many of the authors cited previously have very direct paths from
students’ beginning thinking to the final learning goal, Baroody’s thinking is much more
flexible. He clearly states that there is no singular learning path, and that learning can veer
off in different directions when a student’s understanding changes. He recalls Lesh’s
words, who claimed that learning is not about “ladders” but rather about “branching”
(Lesh, as cited in Baroody, 2011, p.240). In contrast to other trajectories, Baroody’s is
focused on what he calls “big ideas,” an amorphous idea that is best described as not about
details. While the expectation is that every child will move toward the bigger, broad idea, it
is also expected that no single path is the best path, and that every path will be different.
He asserts that even tens of thousands of cases of similar learning paths does not imply that
the same path is true for all students. Interestingly, Baroody is best known for his work
explicating children’s understanding of early counting and addition (Baroody, 1987),
important understandings that informed future work in the Cognitively Guided Instruction
program (Fennema, Franke, Carpenter, & Carey; 1993) and even for the Common Core.
Grain Size
In the previous section we explored the nature of learning trajectory paths, detailing the
degree to which the proposed paths progress linearly or in a more networked fashion.
Another feature that categorizes various learning trajectories is the level of detail
presented. Baroody’s 2011 review of the contemporary state of research on learning
trajectories issued a criticism of Steffe and Battista’s learning trajectory models as too
detailed and complex to be useful for classroom instruction. The intricate and fine-grained
nature of Steffe’s fraction schemes is quite detailed. The detail is remarkable because as it
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is presented (see Norton & Wilkins; 2010, 2012) it is not useful to curriculum planners, let
alone classroom teachers. This is not a criticism of the quality and nature of their work but
rather a criticism of its accessibility. But Baroody’s criticism was not leveled at the
inaccessibility, but rather at the incredibly fine-grained nature of their work because it
tended to remove the teacher from the development process. As a matter of fact, as the
HLT moved away from Simon’s original presentation as a planning tool for teachers and
became a map of student learning, teacher agency was even further reduced. Ironically,
Simon now bases his teaching experiment work on the intricate sequence of scheme
development that was produced by this very same group. In Simon’s recent talk at PME
(2014), he outlined a plan for providing focused instruction including tasks that move
students along the trajectory toward mastery.
A broader-grain learning trajectory than Steffe’s may provide less guidance, but allows for
more flexible paths to learning. For example, Gravemeijer (1999) intentionally retains the
role of the teacher as the leader of classroom activities and learning trajectories are tools to
help teachers interpret student thinking and manage student progress.
Source of the Learning Trajectory
Discipline Logic
The sequence of mathematical tasks and content that is included in curricular materials
has a long tradition: multiplication in third grade, proportional relationships in 7th grade,
etc. have been ingrained in their respective grades for many teachers and curriculum
developers. However, each inclusion is a decision that is made at either the standards or at
the curriculum level. Often the sequence of standards that emerges from tradition has been
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derived from a target goal, which has been parsed into less and less complex skills. As the
composite skills are broken down into intermediary skills and then parsed further until
there exists a long list of sequence lower order skills. A good example of this is the end goal
of graphing an inequality on the coordinate plane. The list of skills that students need in
order to be able to accurately complete this task is long: graphing an equation on the
coordinate plane, distinguishing greater than or equal to from greater than, substitution of
a value for a variable in an expression and evaluating, etc. The topics mentioned here are
merely the middle school level topics, and they are also only the skills necessary – the list
does not include the understandings that are also prerequisites. This hierarchy of
subordinate knowledge theory is best captured by the work of Gagne, who inspired the
strategies for decades of curricular scope and sequence models. Inherently this strategy is
“top-down,” with the end mathematical goals guiding the creation of preceding objectives
(Battista, 2011).
Another byproduct of “top-down” content is the primacy of discipline logic, a term
specifically coined by Stzajn, Confrey, Wilson, and Edington (2012) that was inspired by the
Consortium for Policy Research in Education document on learning progressions within
science education (Corcoran, Mosher, & Rogat; 2003). The direct statement is that learning
progressions “are based on research about how students’ learning actually progresses—as
opposed to selecting sequences of topics and learning experiences based only on logical
analysis of current disciplinary knowledge and on personal experiences in teaching. Ellis
and colleagues found that such a curricular approach was prevalent in curricula worldwide
(Ellis, Weber, & Lockwood; 2014). Furthermore, the discipline logic-focused curriculum
also engendered a classroom focus on “right” and “wrong” answers rather than on a
LEARNING TRAJECTORIES
process-oriented environment. In this setting, evaluative teacher listening (Davis & Simmt,
2003) guides the teachers’ actions in the classroom. Battista (2011) was not describing
evaluative thinking in the following anecdote, but the incident does capture a perfect
example of evaluative listening. Student X is completing a task determining a distance that
is sketched on a grid structure, and the teacher is evaluating the student’s understanding of
linear measurement by interpreting her work. The student work ambiguously shows a “1”
right next to a corner (see figure 4). One teacher observes the “1” and concludes that the
student is just counting one unit when there should have been two units. Another teacher
concludes that the student is confusing area with perimeter because she is counting boxes
instead of side lengths. While the student’s answer is indeed incorrect, neither teacher
asks the student what their thought process might have been. If the student is indeed
counting squares instead of side lengths, that is an entirely different mental concept, and
stage on the learning trajectory, as the student who may not recognize that the inside
corner includes two adjacent sides. The consequences of the interpretation are great
because the student’s response indicates what direction instruction should take at that
point.
Figure 4
When teachers listen evaluatively they are looking for correct and incorrect answers,
and they view the students’ responses as related more to the teacher’s line of questioning
rather than to the students’ line of thinking. In contrast, interpretive listening is
LEARNING TRAJECTORIES
characterized by information seeking intentions. The listener’s goal is to open spaces
between themselves and the student where they are able to establish a common language
and genuinely understand the student’s thinking and as a result, locate their thinking along
a possible learning trajectory. One of the problems with the evaluative approach is that the
teacher can be deceived by incorrect thinking that nevertheless yields a correct response.
A discipline logic focused standard or trajectory does not engender interpretive listening
because the intent is to evaluate responses as right or wrong so that the responses conform
more tightly to the end learning goal.. Moreover, the discipline logic-centered learning
trajectory may also tend to include a fixed instructional sequence. However, one of the
benefits of discipline logic-centered learning is that the instructional sequence is clear and
ordered. In other words, it is less messy.
Developmental Logic
A learning trajectory that is focused on development logic instead of discipline logic is
focused tightly on the thinking and understandings of the students in the class. Ellis
provides a summary table that well represents the different conceptions that are at the
heart of these differences (Ellis, Weber, & Lockwood; 2014).
Learning Progression Learning Trajectory
Construct Concept
Learning Goals Characterizations
Evidence Examples
Tasks Activities
LEARNING TRAJECTORIES
Consider the difference between learning goals and characterizations. “Understanding the
meanings of the power in an exponential expression” is a typical learning goal given in a
learning progression (Ellis, Weber, Lockwood; 2014). A learning trajectory
characterization has a different tone while it is still focused on the same content. For
example, a characterization of student understanding might show that the student can
“coordinate the ratio of any two y-values for any gaps between two x-values.” This
characterization shows that the student is able to understand the values of y and the values
of x and co-relate them, particularly within determined intervals on the graph. This
coordination requires an understanding of power that goes beyond repeated
multiplication. Not only does a characterization represent a deeper level of understanding,
it also provides activities that are designed to directly address particularly challenging
developmental targets.
Learning trajectories, recalling Simon’s (1995) definition, include learning goals,
learning activities, and the thinking and learning in which students might engage. Under a
developmental logic frame, this focus on students in the instructional process is a logical
outgrowth of the learning trajectory structure. One of the key elements is the important
role of instructional tasks in moving students forward in their learning. The van Hieles
(2004) assert that students do not naturally move from one level of geometric thinking to
another- they must have extensive experiences under specific kinds of learning conditions
that give them opportunities to restructure their understandings. Battista also puts great
import on the value of instructional tasks to move through levels, even if the movement
through levels is somewhat erratic and varies according to the task (Battista, 2011).
LEARNING TRAJECTORIES
The developmental logic approach to learning paths is not a haphazard response to
student learning based on anecdotal evidence from a sequence of tasks. The
developmental touchpoints within a learning trajectory are based on empirical evidence
gathered from the research experiences of the writers, other researchers’ accrued
knowledge, as well as from knowledge of how students in the classroom respond to
teaching activities. Nevertheless, the learning trajectory is a “bottom up” point of view, in
that student understandings create the structure of the learning, and the LT itself provides
steps along the way for teachers to look for. But, an interesting recent development is the
apparent reification of learning trajectories that seems to have occurred as each “camp”
produces more evidence that verify their hypothetical learning trajectories. Simon’s recent
presentation at a conference couches a sequence of learning activities and resultant
concepts within the frame of a concept-development set of tasks, contrasting this teaching
strategy with the classic problem solving lesson. He even hinted that this structured series
of tasks is designed to provide the exact right sequence needed to assist students who
struggle with learning to work with fractional rational numbers (Simon, 2014). One came
away with the distinct impression that following this prescribed series of activities would
lead students directly through the projected learning path: the HLT would become the
actual LT! It was a surprising turn.
Confrey’s bridging standards serve a similar role in that they fill in the empty spaces
between widely spaced CCSSM standards, standards that permit multiple access points and
paths (Confrey et al., n.d.). However, Battista credits learning trajectories with predictive
power: an LT will not tell you exactly what a student might do or understand, but it does
engage with probable outcomes (Battista, 2011). In another article Confrey’s team also
LEARNING TRAJECTORIES
asserts that learning trajectories make reasonable predictions of what student
understanding of a concept might be (Sztajn, et al., 2012), which provides guidance for the
teacher to select tasks that will lead students to the next conceptual idea.
In the end, the process of instruction must include both orientations to learning. The
development perspective acknowledges that individuals do not adopt new ideas and
information exactly how they are presented (von Glasersfeld, 1995). Instead they re-create
mathematical understandings that build on their current understandings. That individuals
follow even remotely similar learning paths is surprising if one holds a radical
constructivist point of view. However, no learning would be valuable if none of this
information became taken-as-shared (Davis & Simmt, 2003) and agreed upon by the local
mathematics classroom community. Furthermore, none of the taken-as-shared
information is valuable unless it begins to look more like the language and symbolism of
the outside mathematics community. In this direction, the discipline logic orientation
appears more sensical. Sztajn et al. (2012) state directly that negotiation between the
discipline logic, which is the global taken-as-shared knowledge and norms, and the
developmental logic must come together to form a coherent trajectory. This trajectory
accounts for individuality, but also welcomes the standardized norms that define the
mathematics field.
Learning Trajectory – Learning Progression – Hypothetical Learning Trajectory
This review of research began as an exploration into the differences between the LT
and the LP, and the seemingly random use of all three terms in the literature. The
hypothetical learning trajectory was introduced in 1995 by Marty Simon in a piece focused
on an instructional model that was largely ignored. Instead the HLT has become an
LEARNING TRAJECTORIES
acronym that retains little to none of the meaning with which it was originally imbued.
Hypothetical, in his estimation at that time, referred to the teacher’s conjecture at the
beginning of lesson planning of what students would think and learn as they engaged in a
set of learning tasks directed toward a determined goal. The scope of the HLT was narrow,
limited only to the classroom setting.
The term HLT served a need in the field because it was soon adopted by several other
research teams to describe students’ learning processes. Clements and Sarama, Baroody,
Battista, Confrey, and many more later adopted the learning trajectory term to describe
their new understandings of student knowledge growth. To varying degrees the
“hypothetical” was kept or discarded (ex. Baroody and Gravemeijer). When it was kept, it
ceased to refer to the teacher’s conjectures about hypothetical paths of learning students
might taken. Instead it came to qualify the learning trajectory as “conditional” on further
research, or as a means to make claims and express reasonable hesitation toward
generalizations to entire populations. But, it no longer held the original meaning that was
tied to individual teachers.
Others stopped using the “hypothetical” qualifier and their research findings suddenly
took on a more definitive tone. The learning trajectory emerged as a formidable series of
levels (or schemes, or touchpoints, or nodes, or steps) that students are likely to follow as
they learn within a specific domain.
Finally, it is important to discuss the learning progression, primarily for two reasons.
Much of the cited information given to support the validity of the learning trajectory is
traced back to a single document published by Corcoran, Mosher, & Lockwood (2003). The
document concerns itself with students’ processes as they learn about the big ideas of
LEARNING TRAJECTORIES
science, a discipline which also can be riddled with profound misconceptions. They
adopted the National Research Council’s definition of a learning progression as “Learning
progressions in science are empirically-grounded and testable hypotheses about how
students’ understanding of, and ability to use, core scientific concepts and explanations and
related scientific practices grow and become more sophisticated over time, with
appropriate instruction (NRC, 2007).” This definition more closely aligns to the definition
of learning trajectory currently used in the mathematics education field, and many have
accepted it as their preferred usage.
Secondly, there is a continuously evolving set of documents (McCallum, Daro, & Zimba;
2014) being written for the purpose of elaborating on the standards that form the CCSSO
(2010). These learning progressions more closely resemble a discipline logic approach to
instruction. The CCSS standards certainly have more in common with the discipline logic
as well, but the learning progressions profess to do the same work that Confrey’s hexagon
model (Confrey et al., 2014) does as well: fill in necessary gaps between the broad and far-
reaching standards and begin to unpack the mathematical understandings that underlie the
new standards.
The effort to support the given standards is admirable, but as always with a discipline
logic-based system, conflicts with students’ learning achievements call into question the
appropriateness of the CCSS standards at particular grade levels. There are examples
where the scope and sequence of the national standards is not consistent with students’
potential capacity to learn the standards. One example is the coordination of three levels of
units as students learn to divide fractions. This is a standard that falls within the 6th grade
LEARNING TRAJECTORIES
in the Common Core. At the 2012 NCTM Research Pre-session a panel of researchers
presented a set of empirical findings showing that the skills required to achieve this
particularly objective were not acquired by a significant percentage of the sample
population of the same age in their study (Steffe, Norton, Hackenberg, Thompson, &
Empson; 2012). The generalized conclusion is that if it is not possible, or probable, that the
majority of sixth graders will have achieved a level of mathematical development
sophisticated enough to meet the sixth grade standard, the standard is therefore
problematic. Their suggestion is to reorganize the standards to be more developmentally
appropriate and accessible to most if not all students. This is an example where an
emphasis on the structure of the mathematics, or discipline logic, results in a sequence of
learning goals that are not attainable by a significant portion of the population.
Cautions and Criticisms
Empson wrote a leveled critique of the enthusiasm surrounding the potential of
learning trajectories in guiding curriculum and learning (Empson, 2011). Some learning
domains, she says, are quite naturally prone to follow such predictable paths and cites
early counting skills (Gelman & Gallistel, as cited in Empson, 2011) and multi-digit
multiplication (Fuson, as cited in Empson, 2011) as examples. On the other hand, she
suggests that the learning trajectory research work on rational number understandings by
Steffe & Olive (2010), Behr, Harel, Post, & Lesh; 1992), and others do not suggest one
coherent learning trajectory, which renders their conclusions tenable. One reason may be
the extensive dependence of the LT on the learning tasks that form the structure of the
trajectory. A learning trajectory assessed and therefore driven by a certain set of tasks
LEARNING TRAJECTORIES
looks different from another learning trajectory. In either case, these are cautions for
adopting any learning trajectories in their entirety.
Another of Empson’s (2011) criticisms is the reduction of teacher agency in the current
understanding of the learning trajectory. As the LT models become more tightly defined,
they risk becoming more structured and limiting and less able to account for individual
differences. Doerr (2006) echoes this concern when she expresses concerns that the
stringent demands of the standards environment already limit the expression of students’
generation of models of mathematical understanding. Doerr’s interpretation of the
learning trajectory more closely mirrors Simon’s original interpretation, and she credits
the learning trajectories with providing teachers with opportunities to grow along with
their students and learn about the mathematics as students do the same. Another moderate
and level view is Ellis’ statement: “A more efficacious approach may be one that attends to
the variation in students’ conceptual development, building trajectories of the students’
understanding over time (Ellis, Weber, & Lockwood, 2014, p.3-3).
Conclusion
The topic of learning trajectories offers great promise for teaching practice. The
greatest benefits of the continually evolving research on learning trajectories, as well as
learning progressions, are the guidelines that they provide to teachers as they learn more
about the sequence of students’ learning. Previous curriculum standards and textbooks
employ a discipline logic when structuring their content scope and sequence, and current
teachers are accustomed to this focus. The tasks they develop reflect this orientation and
when engaging with open-ended tasks with a higher cognitive demand, they often are not
able to anticipate the responses their students offer for these tasks. Because students
LEARNING TRAJECTORIES
exhibit unexpected mathematical solutions, teachers are more inclined to abandon these
tasks because they can not yet interpret the responses. More understanding and
experience with learning trajectories that describe students’ mathematical thinking will
give them to the skills and confidence they need to interpret their own students’ work.
However, it is important that the learning trajectories retain a predictive role rather than a
prescriptive role. As the list of expected and anticipated conceptual developments
becomes more rigid and detailed, there is less room for individual variation. In this sense a
learning trajectory that resembles the network/landscape model is most flexible as it offers
a variety of interpretations for examining and interpreting student work in the classroom.
Finally, there is great need for professional development for teachers as they begin to make
sense of the new details of learning trajectories, particularly in those cases where the
trajectory has a developmental orientation rather than a discipline logic orientation.
LEARNING TRAJECTORIES
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