The SMOG Formula: A Complete Guide

Written communication suffers when people have difficulty understanding what they’re…

Written communication suffers when people have difficulty understanding what they’re reading. You might want to assess the readability of your text and make adjustments where necessary. The SMOG formula is a readability testing tool designed to grade a text based on the number of sentences and syllables per word.

This article discusses the SMOG formula and how to use the tool to test the readability of your text.

What is the SMOG Formula?

A good readability formula measures the level of readability of a text by assessing the sentences or words.

The SMOG (Simplified Measure of Gobbledygoop) formula was created by McLaughlin. It is a tool that determines what written content is the most readable with an objective assessment.

SMOG readability formula estimates the years of education an individual needs to comprehend a text. It measures the level of text readability by considering the number of sentences and syllables per word.

SMOG Readability Formula: How it Works

The SMOG readability formula defines a numeric value, known as the SMOG grade, which estimates the readability of a given text. When using the SMOG formula to calculate the reading grade level of your text, consider the following steps:

1: Begin with the entire written text to be assessed.

2: Count off ten sentences near the beginning, 10 in the middle, and ten near the end to make 30 sentences.

3: Circle all the polysyllabic words from the sample of the 30 sentences. Include repetitions of the same word, and total the number of words circled.

4: Find the nearest perfect square of the total number of polysyllabic words and then take its square root.

5: Add a constant of 3 to the figure obtained in step 4 above. The value obtained is the SMOG Grade, i.e., the reading grade level a person must have attained to comprehend the text being assessed fully. SMOG grade = 3 + Square root of Polysyllable Count.

Rules governing the McLaughlin’s SMOG Readability Formula

McLaughlin’s SMOG readability formula is premised upon the following.

1. A sentence is a string of words punctuated with a period (.), an exclamation mark (!), or a question mark (?).

2. Consider long sentences with a semi-colon as two separate sentences.

3. Consider hyphenated words as a single word.

4. Written numbers (spelled out or in numeric form) should also be considered. If written in numeric form, they should be pronounced to determine the number of syllables they have.

5. Proper nouns that are polysyllabic should also be counted.

6. Read abbreviations as though non-abbreviated to determine if they are polysyllabic.

7. To test a written text with fewer than 30 sentences, follow the steps below:

i. Take note of the number of polysyllabic words in the text.

ii. Take note of the number of sentences in the text.

iii. Find the average number of polysyllabic words per sentence by dividing the figure obtained in (i) by that obtained in (ii), i.e.,

Average = Total Number of Polysyllabic Words

Total Number of Sentences.

iv. Multiply the average gotten in (iii) by the number of sentences fewer than 30.

v. Add the figure gotten in (iv) to the total number of polysyllabic words.

vi. Calculate the square root and add the constant of 3.

An easy way to calculate the SMOG reading grade level of a text is by using the SMOG conversion table. Count the number of polysyllabic words in a chain of 30 sentences and look up the approximate grade level on the conversion table.

SMOG Conversion Table

Total Polysyllabic Word Counts Approximate Grade Level
















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To Wrap Up

The SMOG readability formula is used to gauge a written text’s comprehensiveness. It measures the reading grade level a person must have attained if they want to comprehend a written text fully. If the readability is greater than 10, we expect the content to be more challenging to understand.

Frequently asked questions

What is the SMOG formula?

Using SMOG Formula: Count 10 consecutive sentences near the beginning, middle, and end of your material (30 total sentences). 2. Try to count every word with three or more syllables in 30 sentences, even if it appears more than once. 3.

Who developed the SMOG formula?

SMOG Index was created by clinical psychologist Robert G. Guilford. Harry McLaughlin. In order to simplify readability, he created a simple formula. Words with multiple syllabic ssylogabics that included polysyllabbic.

What is a SMOG calculator?

A G-level measure of readability, SMOG (Simple Measure of Gobbledygook), is developed by G-Level readers. This was recommended in 1969 for use by healthcare practitioners. It was designed as an alternative to the Gunning fog index.

How do I know what reading level my text is?

Text readability is determined by the number of words included in the passage that are not on the 3,000-word list. Scores are equivalent to grade levels when the number of unfamiliar words in a text is high (the higher the number).

Why is the smog formula a particularly useful measurement tool?

An evaluator can determine the grade level of patient education by counting 10 sentences at the beginning, middle, and end of a document.

What is new Dale Chall grade level?

7.0 to 7.9Grades 9 – 10
8.0 to 8.9Grades 11 – 12
9.0 to 9.9Grades 13 – 15 (College)
10 and AboveGrades 16 and Above (College Graduate)

What is the SMOG formula used for?

In 1969, Harry McLaughlin wrote about the SMOG Readability Formula in his article SMOT Grading – A New Readability formula in the Journal of Reading. An assessment of the Readability Formula uses the years of education needed to comprehend a piece of writing.

What is a good Flesch Kincaid Grade Level?

It is similar to the US grade level of education. In this article, we learn how to understand a text. A general public should aim for a grade level between 13 and 14 if reading is intended for them.

What are the main components of smog?

The smog, created mainly above cities, is composed mainly of tropospheric ozone (O3); primary particulates such as pollen and dust; and secondary particulate matter such as .

What is smog stand for?

“SMOG” is a word for simple measure of goop. SMOG is widely used to monitor health messages, particularly in mornings. According to the SMOG grade, the correlation between the scores of readers who knew 100% of the test material is 0.985 with a standard error of 1.5159.

The SMOG Formula: A Complete Guide

Pam is an expert grammarian with years of experience teaching English, writing and ESL Grammar courses at the university level. She is enamored with all things language and fascinated with how we use words to shape our world.

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