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Calculating Reading Level
Below are a series of methods whose functions are used to determine the reading levels for different student age groups. Teachers can use these methods to determine whether new material is suitable for their class, and also to determine at what grade levels their students are writing. A few things apply to all methods:
They all require 100-word samples, so anything shorter will not suffice. When counting syllables and words, count any proper nouns, numbers, or dates as one. For instance, “Abraham Lincoln,” “865,460,” “March 23, 1998,” and “Connecticut” would each count as an “easy word” or a one-syllable word. This is because the point is to test the vocabulary of the sample and things like names, numbers, and locations are usually understandable by anyone. For example, most children know the four-syllable word “Arizona” but not the four-syllable word “vicissitude.”
These formulas can be tricky, but by carefully following one step at a time they shouldn’t cause too much difficulty. To help decrease complication I have rounded any decimals to one or two places. Some of the formulas require using decimals up to three or four places, but I have rounded the results which explains how 206.835 - 131.3 = 75.5 as opposed to the more accurate 75.535, but these differences are nearly irrelevant and need not be concerned.
Gunning Fog Index
The Gunning Fog Index is used to determine the readability for upper elementary reading material. Apply the following steps (you may want to use a calculator), and refer to the example to verify the procedure.
First, select a sample of 100 words and count the number of sentences in the sample. Divide the number of sentences into the number of words (100) to find the average sentence length. Now count the number of “big words” (3 syllables or more) and divide 100 by that number to find the percentage of big words (add a decimal point two digits before the number). Add the average sentence length and percentage of big words together and multiply the sum by 0.4 to find the result.
Assume there is a 100 word sample with one 12-word sentence, two 10-word sentences, two 9-word sentences, three 8-word sentences, three 6-word sentences, and two 4-word sentences.
Step 1: Count the number of sentences and find the average sentence length.
1 + 2 + 2 + 3
+ 3 + 2 = 13 sentences
100 / 13 = 7.7 average length
Step 2: Count the number of “big words.” Let us assume that of the 100 words in the sample, 12 of them are three syllables or longer.
12 / 100 = 0.12, or 12%
Step 3: Add average sentence length to percentage of big words and multiply by 0.4. (Use the percentage as a whole number and not a decimal)
7.7 + 12 =
(19.7)(0.4) = 7.88
This sample would be at the 7th grade reading level, close to 8th.
The Flesch Formula: Reading Ease & Grade Level
Here is a more accurate method for upper elementary texts.
Select a 100-word sample and count the number of sentences. Divide the number of words (100) by the number of sentences and multilpy the result by 1.015. Save this result and call it x. Now count the total number of syllables in the sample, divide by the total number of words (100) and multiply by 84.6 (Or just multiply the number of syllables by 0.846 — the results will be the same). Now call this number y. Add x to y and subtract the sum from 206.835. The final result is the Reading Ease Score (see table).
Reading Ease Score Difficulty Flesch Grade Level
· 0-29 Very Difficult Post Graduate
· 30-49 Difficult College
· 50-59 Fairly Difficult High School
· 60-69 Standard 8th to 9th grade
· 70-79 Fairly Easy 7th grade
· 80-89 Easy 5th to 6th grade
· 90-100 Very Easy 4th to 5th grade
We’ll use the same sample used in the first example.
Step 1: Divide number of words by number of sentences and multiply by 1.015. Call the result x.
100 / 13 =
(7.7)(1.015) = 7.8
7.8 = x
Step 2: Count total syllables, divide by 100 and multiply by 84.6. Call this number y. Let us assume the sample contains 146 total syllables.
146 / 100 =
(1.46)(84.6) = 123.5
123.5 = y
Step 3: Add x to y and subtract from 206.835.
7.8 + 123.5 =
206.835 - 131.3 = 75.5
Step 4: Check the table for results.
75.5 falls in the 70-79 category listed on the table above, which classifies the sample as Fairly Easy and assigns a recommended 7th grade level. Notice that this result matches the result used for the Gunning Fog Index — both methods put the sample in the 7th grade level.
Power Sumner Kearl Formula
This is a method of determining the readability of books for elementary school ages.
Find a 100 word sample. Count the number of sentences and divide into the number of words (100) to find the average sentence length. Call this number x. Now count the number of syllables and call that number y. Multiply x by 0.0778 and multiply y by 0.0455, then add the two results and call it z. Find the grade level of the sample by subtracting 2.2029 from z, and find the reading age by adding 2.7971 to z.
We’ll choose a new theoretical sample, since this formula applies to a younger age group than the last two.
Step 1: Count the number of sentences and divide into 100 to find the average sentence length and call the result x. For this example, let us assume there are two 7-word sentences, four 6-word sentences, six 5-word sentences and eight 4-word sentences.
2 + 4 + 6 + 8
= 20 sentences
100 / 20 = 5 average sentence length
5 = x
Step 2: Count the number of syllables and call it y.
Let us assume this 100-word sample contains 112 syllables.
112 = y
Step 3: Multiply x by 0.0778 and multiply y by 0.0455, then add the two results and call it z.
(112)(.0455) = 5.1
0.4 + 5.1 = 5.5
5.5 = z
Step 4: Find the grade level by subtracting 2.2029 from z.
5.5 - 2.2029 = 3.3
This sample should be readable to the average 3rd grader.
Step 5: Find the reading age by adding 2.7971 to z.
5.5 + 2.7971 = 8.3
This theoretical text should be readable for the average 8-year old.