UNIT 4:

Readability Index

Measurement

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What is Readability?

The feature of plain language that makes it easy to read Or

Describes the ease with which a document can be read.

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How to Measure Readability?

Mathematical formulas were designed to assess the suitability of books for students at particular grade levels or ages.

Formulas provide an objective measure of text difficulty that can be reported as a level.

It is interpreted to mean that a reader must be reading at that level in order to understand the text.

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The readability formulas are 80 percent accurate.

They give a good rough estimate of the difficulty of a text.

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Features of the Reader thataffect Readability

Readers:

1. Prior Knowledge

2. Reading skill (literacy)

3. Interest

4. Motivation

Text:

1.Content

2.Style

3.Design

4.Organization5

Benefits of Readability

Greater readability increases:

Comprehension (understanding)

Retention (memory)

Reading Speed

Persistence (reading more of the text)

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Readability Formula

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1. Rudolf Flesch

his Reading Ease Readability formula.

RE = 206.835 – (1.015 x ASL) – (84.6 x ASW) 

RE = Readability Ease 

ASL = Average Sentence Length (i.e., the number of words divided by the number of sentences) 

ASW = Average number of syllables per word (i.e., the number of syllables divided by the number of words) 

http://www.readabilityformulas.com/flesch-reading-ease-readability-formula.php

Scores:

90-100 : Very Easy 80-89 : Easy 70-79 : Fairly Easy 60-69 : Standard 50-59 : Fairly Difficult 30-49 : Difficult 0-29 : Very Difficult /Confusing 

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Flesch Reading Ease score: 

22.8 (text scale)Flesch Reading Ease scored your text: very

difficult to read.

Reading Level: very difficult to read.

Reader's Age: College graduate

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2. Spache Readability FormulaThe Spache Formula considers “unfamiliar words” as words that 3rd grade and below.

Spache Readability Index/Grade Level = (0.141 X ASL) + (0.086 X PDW) +0.839 

where, 

ASL = Average Sentence Length 

PDW = Percentage of Difficult Words 

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http://www.readabilityformulas.com/spache-readability-formula.php

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ADJUSTED SCORE GRADE LEVEL

4.9 and Below Grade 4 and Below

5.0 to 5.9 Grades 5 - 6

6.0 to 6.9 Grades 7 - 8

7.0 to 7.9 Grades 9 - 10

8.0 to 8.9 Grades 11 - 12

9.0 to 9.9 Grades 13 - 15 (College)

10 and AboveGrades 16 and Above (College Graduate)

Spache Readability Index: 15.6

Grade level: College Graduate 

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