Text Readability: A Snapshot

Received Sep 28, 2018 Revised Jan 02, 2018 Accepted Jan 02, 2019 Selecting suitable reading materials are taxing and challenging for many English instructors. Text readability analysis can be used to automate the process of reading material selection and also the assessment of reading ability for language learners. Readability formulas have been broadly used in determining text difficulty based on learners’ grade level. Based on mathematical calculations, a readability formula examines certain features of a text in order to provide best rough approximations as an indication of difficulty. This paper reflects some aspects and issues of readability analysis


DEFINITION OF READABILITY
The concept of readability was initially defined as the interactions of understanding of words, phrases and ideas in a text with comprehension that influence readers' interest, understanding and reading speed (Dale & Chall, 1949). Readability is further explained as "the ease of understanding or comprehension due to the style of writing" (Klare, 1963). This definition highlights the importance of writing style besides aspects like content, coherence and organization. According to McLaughlin (1969), readability signifies the interaction between the text and a group of readers of known characteristics like reading skill, prior knowledge, and motivation. All in all, readability is an attribute of written text, commonly defined by factors that theoretically make a text more or less difficult to read (Begeny & Greene, 2013).

DEVELOPMENT OF READABILITY FORMULAS
Readability formulas were first initiated between 1921 and 1934 where vocabulary was the primary basis to predict readability. Between 1934and 1953, formulas like Flesch (1948, Dale and Chall (1948), Gunning (1952), Spache (1953 and Powers-Sumner-Kearl (1958) that encompassed more and different factors as variables, with less dependency on the Thorndike word count were developed.
The arrival of cloze procedure as a tool for measuring readability in the mid-1950s incited the development of new criteria, new formulae, computerized versions, and the continued testing of text variables (Dubay, 2004). The cloze testing was considered to be relevant in measuring not only the difficulty of the whole written text but also the difficulty of individual words, phrases, and clauses (Bormouth, 1966). Automated Readability Index -ARI (1967), Bormuth Readability Index (1968), Fry's Readability Formula (1968), McLaughlin's (1969) Simple Measure of Gobbledygook (SMOG), FORCAST Readability Formula (1973), Coleman-Liau Readability Formula (1975), Raygor Estimate Graph (1977 and the new Chall and Dale (1995) were later introduced. Since then, more computerized formulas have been developed. Some recent online readability tools

APPLICATION OF READABILITY FORMULAS
Readability can be assessed through readability tests that apply readability formulas. These formulas are mathematical in nature; their primary aim is to measure the grade level a person must have to read and comprehend a text (Grabe, 2009). Readability measures are based on two features of a text -the difficulty of the sentences (usually measured by the number of words or clauses per sentence) and the familiarity of the words (usually measured by the frequency of the words in a large database of texts). To estimate the difficulty of a text, readability formulas commonly use the length of a word or sentence as the indicator of difficulty. It is assumed that longer sentences are harder sentences and longer words are harder words. The computations would calculate the actual scale score and this score would then be compared and interpreted based on an index Grade Level 4.9 and below 4 th Grade and below 5.0 to 5.9 5-6 th Grade 6.0 to 6.9 7-8 th Grade 7.0 to 7.9 9-10 th Grade 8.0 to 8.9 11-12 th Grade 9.0 to 9.9 13-15 th Grade (College) 10.0 and above 16 th Grade and above (College Graduate) Source: Dale, E. & Chall, J.S. (1995). There are many readability measures and though each is slightly different, all of them focus solely on the surface difficulty of the words and the sentences. Applying different readability tools to the same piece of text will provide different scores and different reading levels (Begeny & Greene, 2013). The results of testing therefore depend significantly on which readability tool is used.

SIGNIFICANCE OF READABILITY FORMULAS
Studies have shown that readability formulas are useful and have been widely accepted. Fry (1968), for instance, has stated that a lot of "good deal has been written about them" (p.513). Readability tools are helpful in objectively analysing texts and this veracity has made them more likely to be reliable and trusted. Rubin and Bolt (1981, p.5) reaffirm that "readability formulas are available, objective, economical, and established".
Print materials used in classrooms may benefit from the use of an objective quantitative measurement of readability. Rush (1984, p.4) states that "readability scores can be used to determine the grade-level appropriateness of materials ranging from library books and periodicals, to instructional materials in subjects such as social studies, science, mathematics, health, and even reading".
The formulas provide unbiased results that language instructors can trust to predict the level of readability in broad terms. The readability scores would give rough estimations as to whether the selected materials are pitched at a level of readability appropriate for the reading stage of the students. The outcome of the readability analysis not only minimizes time and effort but also avoids the "trial and error" reading practice in deciding the text difficulty.
Since readability formulas are text-based formulas; they are easy-to-use. Calculations using the formulas can be done by hand or by using computerized versions that are built into word processing programs or other software. The online readability tools are very user-friendly. A user is only required to paste a sample or an excerpt of a text (150-3000 words) in a box and clicks on a button to analyse a text. The online readability tools will then analyse the text and output the results based on several readability formulas. These tools will also assist the user to determine the grade level for the text. Automatic Readability Checker, Readable and Readability Calculator are some of the online tools that can assess texts using several renowned formulas such as Flesch-Kincaid Grade Level, the Gunning-Fog Index, Coleman-Liau Index, ARI (Automated Readability Index), and SMOG in a simultaneous manner.
Readability tools can also inform whether any changes that have been made to the text are really making it clearer. In addition, readability formulas can also enhance readers' retention, comprehension and reading speed.

DOWNSIDES OF READABILITY FORMULAS
Despite the progressive and rapid development of the readability formulas, they still remain deficient. One of the shortcomings of these formulas is their incapability to cater struggling readers, learning-disabled readers and also ESL/EFL learners. In addition, there is a tendency that the readability results may underestimate the difficulty of the reading materials (Mesmer, 2008).
Another constraint of the readability formulas is their ignorance towards other factors that may ease reading and influence comprehension. According to Armbruster et al., (1985, p.8) "readability formulas fail to take into account many characteristics of a text that are known to affect comprehension, for instance content difficulty and familiarity, organization of ideas, author style, page layout". In addition, the formulas also ignore the active role of the reader thus they can only determine the level of readability for a wide range of students in general.
Another drawback is the inconsistent readability scores for the same text. Readability formulas vary in which attributes of words and sentences they take into account and how they measure them. For instance, the Flesch Reading Ease Score calculates the total number of words in each sentence, and then the total number of syllables in each word while the Automated Readability Index (ARI) calculates based on characters per word instead of syllables. With different formulas, the scores for the same text can sometimes differ by two, three, or more grade levels (Pitcher & Zhihui, 2007). For example, Flesch-Kincaid scores tend to underestimate actual reading grade level because they are often several grade levels below the results obtained by other measures (Root & Stableford, 1998).

CONCLUSION
In order to meaningfully use readability formulas, language instructors should understand and realize what these formulas actually measure as well as their limitations. Readability scores can be used as a quick screen for difficulty of words and sentences but not as indicators of comprehension.
The scores exhibit only one of many factors that can influence the ease of reading and the usability of reading materials.