An article in WebsiteMagazine.com (June issue) dealt with writing better business blogs. It covered the usual stuff, but pointed out two web sites to assess and, perhaps, improve readability.
Readability tools measure the educational level necessary to understand the material. These tools use measures of words per sentence, syllables per word, and other proxy measures of difficulty. Microsoft Word will generate a number of these via its proofreading tools. Below is the information for a one-page agreement for my son to play American Legion baseball this summer:
The analysis starts with basic count of words, characters, paragraphs, and sentences. The program then calculates sentences per paragraph, words per sentence, and characters per word. The first readability indicator, the percentage of passive sentences, has been addressed in earlier posts. Flesch Reading Ease purports to measure just that, with higher scores being easier. The Flesch-Kincaid Grade Level presents the years of school needed to understand the text.
What if you work online rather than in Microsoft Word? The article presents two websites that can measure readability by URL. I tested a recent post of mine on stereotype threat, first at www.read-able.com, which generates the following scores:
Flesch Kincaid Reading Ease
Based on a 0-100 scale. A high score means the text is easier to read. Low scores suggest the text is complicated to understand.
206.835 - 1.015 x (words/sentences) - 84.6 x (syllables/words)
A value between 60 and 80 should be easy for a 12 to 15 year old to understand.
Grade Level indicators
These equate the readability of the text to the US schools grade level system.
Flesch Kincaid Grade Level
0.39 x (words/sentences) + 11.8 x (syllables/words) - 15.59
Gunning Fog Score
0.4 x ( (words/sentences) + 100 x (complexWords/words) )
1.0430 x sqrt( 30 x complexWords/sentences ) + 3.1291
Coleman Liau Index
5.89 x (characters/words) - 0.3 x (sentences/words) - 15.8
Automated Readability Index (ARI)
4.71 x (characters/words) + 0.5 x (words/sentences) - 21.43
Coleman Liau and ARI rely on counting characters, words and sentence. The other indices consider number of syllables and complex words (polysyllabics - with 3 or more syllables) too. Opinions vary on which type are the most accurate. It is more difficult to automate the counting of syllable as the English language does not comply to strict standards!
So how did my post on a fairly complex topic with lots of pull quotes do?
Click to enlarge
For a general adult audience in the US, experts recommend a Reading Ease score of 60-70; Reader's Digest comes in at 65 while Harvard Law Review scores about 30.
Four indices show easy readability, while the Reading Ease score suggests a more difficult text. The Coleman Liau index suggests the text would be moderately challenging for most adults.
Another site, Juicy Studio, offers many of the same tests, but with more information on the scores. Here is a table they post on typical Gunning-Fog scores:
Click for source
How did my post do at Juicy?
The two sites must not calculate in the same manner. Read-able gave my post a less readable score for Reading Ease and a higher Grade Level than the Juicy site. However, the Gunning Fog index on Juicy suggested the post was written at the level of Time Magazine, while Read-able put it at the level of Reader's Digest.
The scores suggest that my blog writing hits the right level for this audience; when I write medical information for families, I keep the grade level 5-6 and the Reading Ease close to 70 so all of the people I serve can understand it. Of course, our baseball team produced a document that players (13-18 years old) and their parents had to sign that tests out far more difficult than my sample blog post. Someone should probably revise that document!