Readability statistics: measuring how well you write

14 May 2013

A colleague has just asked me about readability statistics. People don't always find them on Word; and when they do find them, they don't always know what they mean.

So here's a quick guide.

First, find your statistics.

In Word 2007:

When you have opened a Word file, with lots of text in it, go to 'Review'.
Click on 'ABC Spelling and Grammar'.
In the dialogue box, click the 'Options' button (bottom left).

In the next box, tick the box marked 'Show readabiity statistics'.
Click 'OK'.
Now run the grammar check. At the end of the process, a set of readability statistics will appear.

In Word 2003:

click on the Tools drop-down menu;
then Options;
then the Spelling and Grammar tab;
toward the bottom of the tab, under Grammar, make sure the Show readability statistics is checked.
Now, run spelling and grammar check through your document. At the end of the process, the readability statistics will appear.

The readability pop-up has three areas.

Counts

The first area – Counts – tells you how many words, characters, paragraphs, and sentences are in your document. Though you might not need to know how many characters your document has, knowing your wordcount is often helpful.

Averages

The second area of readability statistics shows you:

the average number of sentences you have per paragraph;
the average number of words in your sentences; and
the average number of characters per word in your text.

These are valuable measures. Remember that they are averages.

Target numbers for each average are roughly as follows.

Sentences per paragraph: aim for at least 3; preferably a number somewhere between 3 and 5.

Any paragraph with fewer than two sentences probably won’t be developing its topic adequately. Any paragraph with more than six or seven sentences may be wandering or going into too much detail.

Words per sentence: aim for a number between 15 and 20.

If the number is over 20, you probably have a few too many long sentences around (remember, it’s an average.) And a number lower than 15 may suggest that you are writing too many short sentences: ok for a child or language learner, but probably not for your usual readership. The most common problems with sentence length are that writers produce sentences that are too long or too complicated.

Characters per word: aim for a number between four and six.

English uses lots of very short words; if this average goes too high, it means you are using too many long words.

Readability statistics

This section gives you three scores.

Passive sentences

The first measure is of the number of passive sentences you have written. The passive voice means that the object of a sentence has something done to it. (“The ball was thrown by Jim.”) This differs from the active voice, where the subject is doing something (“Jim threw the ball.”)

We prefer active verbs to passive ones. Passive verbs are not incorrect. You might want to use a passive verb when you don’t know who did something, or you don’t want to admit it (“A mistake was made in processing the application…”). Passive verbs have other uses, too. On the whole, though, prefer active verbs to passive ones.

I'd say a passive sentence score of 10% or less is acceptable.

Transform as many passives into actives as you can.

Flesch-Reading Ease Score

This is based on a 100-point scale. The higher the score, the easier it is to understand your document. It’s pretty hard to achieve a score higher than about 60.

Aim for 45-50.

Flesch-Kincaid Grade Level score

This score relates to US school grade levels. A score of 8.0, for instance, means that your writing it geared toward an eighth grade reading level.

For those of us not in the US, grade levels relate to actual age as follows.

1st Grade 6–; 2nd Grade 7–8;3rd Grade 8–9; 4th Grade 9–10; 5th Grade 10–11; 6th Grade 11–12; 7th Grade 12–13; 8th Grade 13–14; High school: 9th Grade (Freshman) 14-15; 10th Grade (Sophomore) 15-16; 11th Grade (Junior) 16-17; 12th Grade (Senior) 17–18.

So a Flesch-Kinkaid Grade Level score of 10 will mean that you are aiming roughly at ‘an educated reader’ of about 15 years old. I suppose we could correlate this to a 'reading age' of 15 - which is, apparently, the average reading age of the British public.

It's all rather complicated.

To keep matters simple, we can say:

the best score to aim for is somewhere between 9 and 11.

It’s important to note that Word generates these statistics mechanically. I'm not at all sure how accurate they are. But they do alter if you edit a piece of text well. They offer some kind of objective measure of the quality of a piece of writing.

So readability stats can also inform a conversation between you and your manager about what constitutes good writing.

Posted at 08:41 AM in Writing | Permalink | Comments (1)