I subscribed to ScribeSEO a while ago and really enjoy it. One of the nice report items inside of it is the Flesch-Kincaid Readability Score of your article. Wikipedi has the equations used to calculate these scores. Since the equations are easy to program, I thought scores from various sources would be very close.
I was wrong!
I wanted to compare the score from ScribeSEO to other tools so I went in search of other readability score tools. The source was an article I wrote about synthetic stock options. It’s not pure text as it has some math in it so perhaps it was a bad source, but it was a real article so I wanted to see how these tools scored it:
Flesch-Kincaid Reading Ease: 60.5
Flesch-Kincaid Grade level: grade level of “7th or 8th grade.”
Their range was 60-70 for the grade so I assume it was nearer the upper range, or 8th grade level.
In Microsoft MacOffice 2011
Flesch-Kincaid Reading Ease: 73.6
Flesch-Kincaid Grade level: 6.7
The Readability Test Tool at http://www.read-able.com.
Flesch-Kincaid Reading Ease: 80.7
Flesch-Kincaid Grade level: 4.3
Flesch-Kincaid Reading Ease: 45
Flesch-Kincaid Grade level: 14
Flesch-Kincaid Reading Ease: 59.49
Flesch-Kincaid Grade level: 11.71
Flesch-Kincaid Reading Ease: 64.40
Flesch-Kincaid Grade level: 11.10
Flesch-Kincaid Reading Ease: 73.67
Flesch-Kincaid Grade level: 4.88
Flesch-Kincaid Reading Ease: 81.4
Flesch-Kincaid Grade level: 7.6
The other readability calculators I found were old, limited in number of characters you could check or downloadable software.
Putting it all together, we have:
So what does this mean to me?
There is a LOT of variation between tools. Don’t just use one tool and assume it is correct. As you can see, no two are the same and they are all using the same equations! I’ll keep using ScribeSEO as my primary tool. The Grade Level is very close to the average of all of the tools. I’ll compare to MacOffice 2011 since it is on my computer, handy, reasonably fast and in the middle of the pack with the numbers.
If you do more testing with other text, I’d be curious what you find out!
Oh.. I checked this article with ScribeSEO and I had a Reading Ease score of 48.77! I suspect these tools don’t work well with reports like this.
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