Measuring the Readability of Printed Educational Materials The readability of printed educational materials (PEMs) is a crucial factor in patient education. Ensuring that PEMs are written at an appropriate level for their intended audience helps to improve comprehension and adherence to health recommendations. Various readability formulas have been developed to objectively assess the reading level required to understand these materials. In this article, we will explore some of the most commonly used readability formulas, including the Flesch-Kincaid scale, the Gunning Fog Index, the Fry Readability Graph, and the SMOG formula.
Readability Measurement Formula for Printed Educational Material
Readability formulas are mathematical tools used to measure the ease with which a reader can understand a text. These formulas analyze features such as sentence length, word complexity, and vocabulary difficulty to provide an estimate of the reading grade level needed to comprehend the material. Readability formulas are commonly used in healthcare to ensure that patient education materials are accessible to a broad audience, including those with limited literacy skills.
Each formula has its unique approach and purpose, and some are better suited for specific types of materials or target populations. The most widely used formulas in healthcare settings include the Flesch-Kincaid Scale, the Gunning Fog Index, the Fry Readability Graph, and the SMOG formula.
Flesch-Kincaid Scale Formula to Measure Readability
The Flesch-Kincaid formula is one of the most widely used tools for measuring readability. It was developed in the 1940s by Rudolph Flesch and later modified by J. Peter Kincaid. The Flesch-Kincaid formula is particularly useful for assessing materials that fall between a 5th-grade reading level and college-level texts.
The Flesch-Kincaid formula is based on two primary variables:
- Average sentence length (measured in words), and
- Average word length (measured in syllables per 100 words).
To calculate the readability of a text, the formula uses these two variables to generate a reading ease (RE) score. A lower score indicates more complex material, while a higher score suggests easier readability.
The formula is well-known for its simplicity and effectiveness in evaluating a variety of materials, including news reports, government publications, and adult educational materials. Because of its ease of use, the Flesch-Kincaid formula is commonly integrated into word processing software, such as Microsoft Word, allowing educators and healthcare professionals to quickly assess the readability of their materials (Flesch, 1948; Spadero, 1983; Spadero, Robinson, & Smith, 1980).
Fog Index to Measure Readability
The Gunning Fog Index, developed by Robert Gunning in 1968, is another widely used formula for measuring the readability of written material. The Fog Index is designed to estimate the years of formal education a reader would need to understand a text on the first reading. The formula is based on two key elements:
- Average sentence length, and
- The percentage of multisyllabic words in a 100-word sample.
The Gunning Fog Index is particularly well-suited for evaluating materials from the 4th-grade level through college level. One of the advantages of the Fog Index is its simplicity. Unlike other formulas, it does not require counting the syllables of every word in a passage, making it quicker and easier to use. The rules for calculating the Fog Index are straightforward, and the formula is based on a short, 100-word sample, which makes it convenient for use in a variety of settings (Spadero, 1983; Spadero et al., 1980).
The Fog Index is often used in healthcare to evaluate the readability of patient education materials, especially when time is a constraint, as it provides a quick and fairly accurate estimate of the difficulty level of a text.
Fry Readability Graph Extended for Printed Educational Material
The Fry Readability Graph, developed by Edward Fry in the 1960s, is a visual tool used to assess the readability of printed materials. It is well-known for its simplicity and ease of use, making it a popular choice among educators and healthcare professionals. The Fry formula can be used to evaluate materials ranging from 1st-grade to college-level texts, making it one of the most versatile tools for readability assessment.
To use the Fry Readability Graph, the evaluator selects three 100-word samples from the text. For each sample, two language elements are measured:
- The number of syllables, and
- The number of sentences.
These two elements are then plotted on the Fry graph, which provides an estimate of the reading grade level of the material. If the text being analyzed is very long (such as a book or an extensive document), six 100-word samples may be used to ensure accuracy (Fry, 1968, 1977; Spadero et al., 1980).
The Fry formula is especially useful for evaluating books, pamphlets, and brochures, which are commonly used in patient education. It is one of the few readability formulas that does not require extensive calculations, and with some practice, it takes only about 10 minutes to determine the readability level of a document.
SMOG Formula for Readability Measurement
The SMOG (Simple Measure of Gobbledygook) formula, developed by G. Harry McLaughlin in 1969, is one of the most popular and reliable tools for assessing the readability of patient education materials. The SMOG formula is widely regarded as one of the most valid and accurate readability tests, particularly for healthcare materials.
The SMOG formula is based on the number of polysyllabic words (words with three or more syllables) within a set number of sentences. The formula provides a grade-level estimate of the readability of the material, typically ranging from 4th grade to college level (Doak et al., 1985).
One of the key advantages of the SMOG formula is its accuracy. Studies have shown that the SMOG formula can evaluate the readability grade level of PEMs to within 1.5 grades of accuracy (Myers & Shepard-White, 2004). This makes it particularly useful in healthcare, where precision is essential for ensuring that patients can understand important health information.
Compared to other readability formulas, the SMOG formula tends to generate higher grade-level estimates. For example, SMOG results are usually about two grades higher than those calculated by other formulas, such as Flesch-Kincaid (Spadero, 1983). This is because the SMOG formula places a stronger emphasis on the presence of complex, multisyllabic words, which are often more challenging for readers.
The SMOG formula has been extensively used to evaluate patient education materials, and it is particularly valued for its speed and ease of use. It is one of the most accurate tools available for assessing the readability of healthcare materials, especially when computerized resources for analysis are not available (Meade & Smith, 1991; Wang et al., 2013).
Conclusion
Readability formulas are essential tools for ensuring that printed educational materials, especially those used in healthcare, are accessible and understandable to their intended audience. Each formula has its strengths and limitations, but when used correctly, they can help educators and healthcare professionals create materials that align with the literacy levels of their patients. The Flesch-Kincaid, Gunning Fog Index, Fry Readability Graph, and SMOG formulas are some of the most widely used tools for measuring readability, and they provide valuable insights into the complexity of PEMs.
By using these formulas, nursing educators and healthcare providers can ensure that their materials are appropriate for the literacy levels of their audience. It is critical to pretest patient education materials using one or more readability formulas to ensure that they are accessible to patients and promote understanding, compliance, and better health outcomes.