What is the SMOG Readability Test?

The SMOG readability formula is a tool used to evaluate the reading level of text. It calculates a score based on the number of polysyllabic words in a sample of 30 sentences, providing a grade level that indicates the education level required to understand the text.

Why Use the SMOG Readability Test?

Using the SMOG readability test can help you:

• Assess the readability of your content.
• Ensure your text is appropriate for your target audience.
• Improve the clarity and effectiveness of your writing.

Understanding the SMOG Readability Test

The SMOG readability test (Simple Measure of Gobbledygook) is a formula that estimates the years of education a person needs to understand a piece of writing. Developed by G. Harry McLaughlin in 1969, the SMOG readability formula focuses on sentence complexity and polysyllabic words to determine text difficulty. Unlike other readability formulas that measure various text elements, the SMOG readability test specifically examines the relationship between polysyllabic words and reading comprehension, making it particularly valuable for health communication and educational materials.

What is the SMOG Readability Test?

The SMOG readability test is a widely respected formula used to determine the reading grade level required to comprehend a text. SMOG stands for “Simple Measure of Gobbledygook,” aptly named to highlight its purpose of cutting through complex language. This formula calculates readability by measuring polysyllabic words (words with three or more syllables) within a sample of sentences.

What makes the SMOG readability formula unique is its high correlation with reading comprehension tests. While other formulas might indicate a text's grade level, the SMOG index readability score specifically predicts the education level needed for 100% comprehension of the material, making it more stringent than formulas that aim for lower comprehension levels.

History and Development of the SMOG Formula

G. Harry McLaughlin developed the SMOG readability formula in 1969 while working at Syracuse University. As an editor and educator, McLaughlin recognized the need for a more accurate readability measure than existing formulas like the Flesch-Kincaid readability test.

McLaughlin's innovation came from his observation that the product of the percentage of polysyllabic words and the average sentence length correlated strongly with reading difficulty. He published his findings in the article “SMOG Grading: A New Readability Formula” in the Journal of Reading.

The formula gained particular traction in healthcare communication because of its accuracy and reliability. Health professionals appreciated that the SMOG formula aimed for complete comprehension rather than partial understanding, which is crucial when communicating vital health information.

How to Calculate SMOG Readability: Step-by-Step Guide

Manual SMOG Calculation Process

• Select 30 sentences from your text (10 from the beginning, 10 from the middle, and 10 from the end)
• Count every word with three or more syllables (polysyllabic words)
• Calculate the square root of the total number of polysyllabic words
• Add 3 to the result
• The final number represents the reading grade level

This calculation provides the grade level a reader needs to have completed to fully comprehend the text. For example, a SMOG score of 12 indicates the reader needs a 12th-grade education to understand the material completely.

SMOG Readability Formula for Long Texts (30+ Sentences)

For longer texts, the standard SMOG readability formula applies:

SMOG grade = 1.043 × √(number of polysyllabic words × (30 ÷ number of sentences)) + 3.1291

Let's look at a SMOG readability formula example: If you count 42 polysyllabic words in 30 sentences, the calculation would be: 1. √42 = 6.48 2. 6.48 + 3 = 9.48 3. Round to 9.5

This text would require a 9th to 10th-grade reading level for full comprehension.

SMOG Readability Formula for Shorter Texts (Less than 30 Sentences)

For texts with fewer than 30 sentences, a modified approach is necessary:

1. Count the number of sentences (n)
2. Count the number of polysyllabic words (p)
3. Calculate: SMOG grade = 1.043 × √(p × (30 ÷ n)) + 3.1291

For instance, if you have 15 sentences with 20 polysyllabic words: 1. 20 × (30 ÷ 15) = 20 × 2 = 40 2. √40 = 6.32 3. 6.32 + 3 = 9.32 4. Round to 9.3

This adjustment ensures accurate SMOG index readability scores for shorter texts while maintaining the formula's integrity.

How to Interpret SMOG Readability Scores

SMOG scores directly correspond to U.S. grade levels: - Score of 5-6: Elementary school level - Score of 7-8: Middle school level - Score of 9-10: High school freshman/sophomore level - Score of 11-12: High school junior/senior level - Score of 13-16: College level - Score of 17+: Graduate level

When interpreting SMOG readability scores, remember that the average American reads at approximately an 8th-grade level. Materials intended for the general public should aim for a SMOG score of 8 or below to ensure widespread comprehension.

What is a Good SMOG Score for Different Audiences?

What is a good SMOG score depends entirely on your target audience:

• General public materials: 6-8
• High school students: 9-10
• College students: 11-13
• Academic or specialized professional content: 14-18

For health materials, the CDC and NIH recommend aiming for a SMOG score of 6-8 to ensure accessibility for patients with varying literacy levels. Patient education materials with scores above 10 may present comprehension barriers for many patients.

For marketing content, a SMOG score of 7-9 typically balances accessibility with sophisticated messaging. News articles generally target a SMOG score of 9-11, while legal documents often score 15 or higher.

SMOG vs. Other Readability Formulas (Flesch-Kincaid, Fry, Gunning Fog)

While several readability formulas exist, they differ in methodology and application:

• SMOG: Focuses on polysyllabic words and aims for 100% comprehension
• Flesch-Kincaid readability test: Measures sentence length and syllables per word, aiming for 75% comprehension
• Fry readability calculator: Analyzes sentences and syllables using a graph method
• Gunning Fog: Considers sentence length and complex words, targeting 90% comprehension
• Automated readability index: Relies on characters per word rather than syllables

The SMOG formula is often preferred in healthcare and educational settings because it's more stringent, aiming for complete rather than partial comprehension. However, using multiple formulas can provide a more comprehensive assessment of text readability.

Using SMOG for Health Communication Materials

The SMOG readability test has become a standard in health communication due to its accuracy and reliability. Health literacy research shows that patients better understand and retain information when materials match their reading ability.

When creating health materials: - Aim for a SMOG score of 6-8 for general patient education - Use lower scores (5-6) for critical information like medication instructions - Consider cultural and linguistic factors alongside readability - Test materials with the target audience when possible

Healthcare organizations like the CDC, WHO, and NIH all recommend the SMOG formula for assessing patient education materials, making it an essential tool for health communicators.

Online SMOG Readability Calculators and Tools

Several online tools can calculate SMOG scores automatically:

1. Readable.com - Offers comprehensive readability analysis including SMOG
2. WebFX Readability Test Tool - Free tool that calculates multiple readability scores
3. Online-Utility.org - Provides detailed readability statistics
4. Hemingway Editor - Highlights readability issues while providing SMOG scores
5. Microsoft Word - Has built-in readability statistics including SMOG (must be enabled)

These tools save time and reduce calculation errors, though understanding the manual process helps users interpret results more effectively.

Limitations of the SMOG Readability Formula

While valuable, the SMOG readability formula has several limitations:

1. It doesn't account for reader background knowledge or motivation
2. Technical terminology necessary in some contexts will always increase scores
3. It doesn't evaluate content organization, visual elements, or design
4. Cultural and linguistic nuances aren't captured
5. The formula may penalize necessary technical terms in specialized content

These limitations highlight why readability formulas should be one component of a comprehensive content evaluation strategy rather than the sole determinant of text quality.

Tips to Improve Your SMOG Readability Score

To lower your SMOG score and improve readability:

1. Replace polysyllabic words with shorter alternatives when possible
2. Break long sentences into shorter ones
3. Use active voice instead of passive constructions
4. Define technical terms when they must be used
5. Organize content with clear headings and bullet points
6. Use concrete examples rather than abstract concepts
7. Eliminate unnecessary jargon and acronyms
8. Test your content with representative readers

Remember that improving readability isn't about “dumbing down” content but making information more accessible to your audience. The goal is clear communication, not simply achieving a specific SMOG score.

By understanding and applying the SMOG readability test appropriately, you can create more effective, accessible content that reaches your intended audience with clarity and impact.