how fpa made me a better ba

Robert T. Merrill, Principal

uFunctional LLC

How Function Point Analysis Made Me a Better BA

WI BADD® 2012

2w w w . u f u n c t i o n a l . c o m

Objectives

1. Reinforce User View focus for Stakeholder Requirements

2. Use Application Boundary to clarify scope

3. Leverage File Type Referenced for Requirements Analysis

Make an informed recommendation about using Function Point Analysis in your firm

05/01/2012 ©Robert T. Merrill


What is Function Point Analysis?“Function Point Analysis is a standard method for measuring software development from the user’s point of view.” –CPM 4.2, p2-2

Late 70’s Allan Albrecht (IBM)1984 First publication1986 IFPUG founded2003 CPM 4.2 adopted as ISO Standard


w w w . u f u n c t i o n a l . c o m

Agile “Story Points?”


Function PointsAbsolute

User view only

Correlated w/effort

Compare projects

Beginning & end

Selection & set-up

Story PointsRelative

Implementation view too

Estimates of effort

Within a project

In progress

Project Management


Example Requirements


“Chirper” Requirements

1. I can create a Chirper profile including a username and password, log in, and log out

2. I can search Chirper for Chirps containing a keyword and/or Chirper name, anonymously

3. As a logged-in Chirper, I can send a Chirp (up to 140 characters)

4. As a logged-in Chirper, I see my recent Chirps and Chirps of people I’m following

5. As a logged-in Chirper, I can follow and un-follow other Chirpers

6. As a ChirpMeister, I can delete objectionable Chirps

7. As a ChirpMeister, I can disable the accounts of evil Chirpers.


Example—Logical Data Model


Chirper• Username• Password• Name &

photo• Login state• Disabled?

Chirp• Chirped by• Text string with

$keywords• Time chirped

Followed Chirpers

ChirpMeister• Credential


Example—Data Elements


• ILF—maintained• EIF—referenced only• RET—Record Element Type (“not quite an

ILF”)• DET—Data Element Type, a.k.a “Field”


Example—Xactional Functions


• Input EI, Query EQ, “Output” EO (side effects)

• FTR=File Types Referenced


Determine Complexity


#RET, #DET, #FTR => Low, Average, or High

Data Elements

Transactional Functions


Determine Points


Data 5-15 pointsTransaction 3-7 points


Add them up


ILFs, 21 (3 at 7)EIs, 21 (7 at 3)EOs, 9 (1 at 4, 1 at 5)EQs, 3 (1 at 3)

54 Function Points


What’s FPA good for?

• The Great Normalizer: $$/FP, defect/FP, etc.

• Estimation, especially early

• Process improvement



What’s FPA good for?


Jul-98 Dec-99 Apr-01 Sep-02 Jan-04 May-05 Oct-06 Feb-08 Jul-090.1

1.0

10.0

100.0

App Dev Projects -- Efficiency over time

Hours/Delivered FP

Ship Date

Ho

urs

/Del

iver

ed F

un

ctio

n P

oin

t

(Robert’s MS Ac-

cess projects)2000 2005

10

1

0.1

100Productivity Gains

Hoursper FP


Why I learned FPA


And it made me a better Business Analyst!

Project Estimates for Proposals

• Independent of other estimates

• More convincing

• Minimal added effort


Concept #1: User View

“A user view represents a formal description of the user’s business needs in the user’s language…A function point count is accomplished using the information in a language that is common to both user(s) and developers.” –CPM 4.2, p3-2.


“But how would a user talk about it?”—exasperated Function Point trainer


User View—Practice


“An ILF is a user-identifiable group of logically related data or control information maintained within the boundary of the application. The primary intent of an ILF is to hold data maintained through one or more elementary processes…” CPM 4.2, p6-3.

Chirper• Username• Password• Name &

photo• Login state• Disabled?

ChirpMeister• Credential

• One ILF, or two?• Why?


Concept #2: App Boundary

“The application boundary:• Is dependent on the user’s external business

view of the application. It is independent of technical and/or implementation considerations

• Acts as a “membrane” through which data processed by transactions (EIs, EOs, and EQs) pass into and out from the application

• Encloses the logical data maintained by the application (ILFs)”

—From CPM 4.2, p5-41705/01/2012 ©Robert T. Merrill


Visualizing Scope


Before FPA After FPA

In ScopeLorem ipsumDolor sit amedConsectetur adipiscing Elit phasellus fringilla

Out of ScopeFaucibus libero Quisque sed dapibus


App Boundary—Practice


“Chirper” Enhancements

1. ChirpMeisters log in through a separate screen and authenticate against our enterprise directory.

2. I can log into Chirper using my Friendface username and password, and Chirper will populate my profile if I allow it in Friendface.

Chirper

ChirpMeister

Chirp (text)

Friendface Profile

Directory Profile

• Where’s the app boundary?

• What (if anything) goes away?

• Which are ILFs and EIFs?


Concept #3: FTR

A file type referenced is• An internal logical file read or maintained by a

transactional function or• An external interface file read by a

transactional function—CPM 4.2, p7-13

05/01/2012 2005/01/2012 ©Robert T. Merrill


FTR Example

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I can log into Chirper using my Friendface username and password, and Chirper will populate my profile if I allow it in Friendface.

Chirper

Chirp (text)

Friendface Profile

Directory Profile

• What are the FTRs?FTR

FTR


FTR Practice

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Chirper Enhancement

As a Chirper writes a Chirp, the system auto-completes keywords as they match a list of sponsored keywords or keywords the Chirper has used before.

Chirper

Chirp (text)

• What data functions (logical files) need to be added?

• Are they external (EIF) or internal (ILF)?

• What transactional functions might we need to add?Sponsored

Keywords

Keywords

Add/Edit Sponsored Keyword

Report Sponsored

Keyword Use


Implied Requirements

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1. Functional requirements expose implied data

2. Implied data must come from somewhere

3. Implied maintained data (ILFs) expose implied functional requirements

4. Implied application interfaces (EIFs) expose implied integration points

5. Exposed functional requirements and integration points may expose additional stakeholders!


Implied Requirements

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Logical File

Stated “I can <<verb>> with <<noun>>.”

What are my FTRs?

ImpliedILF

Where’s the app boundary? Where am I maintained?

Implied

Implied EIF


The power of FTR and ILF

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FPA makes you check every:

• Functional requirement against your data model to determine the FTRs

• Logical file for Inputs and Outputs (queries with side-effects) to determine where it’s maintained (ILF or EIF)


Implied requirements exposed


SAVED!


Implied requirements practice


(Distribute handout if we have time.We probably won’t.)


Objectives—Review

1. User View

2. Application Boundary

3. File Types Referenced


“But how would a user talk about it?”

“Walk around the app!”

“What data does this function touch?”“Where are these data maintained?


Thank You!

Robert T. [email protected]@rtmerrill


how fpa made me a better ba

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