A week may be a long time in politics but in blogging, anything that old is positively prehistoric. Never mind, I will nonetheless let you know, courtesy of a link from Dave Lull sent "ages" ago, that you need to have had roughly 11.5 years of "schooling" to be able to understand Petrona — 13 per cent of words have three or more syllables, and there are an average of 15.6 words per sentence, according to the algorithm over at Juicy Studio , where you can see the full gory details (a table) for this or any other website. Just enter the url and off you go.
The Gunning-Fog readability index of Petrona (11.47) is about the same as that of the Wall St Journal, apparently; this is higher than Time and Newsweek (10 each) and lower than The Times and the Guardian (14 each). I’m surprised that the index rates WSJ lower than the Times and Guardian. Academic papers weigh in at 15-20.
Many years ago — before blogs were a twinkle in the eye — we ran a Commentary in Nature about an algorithm to measure readability of text, including scientific articles. The author, a Professor Hayes, created his own algorithm for the purpose, which last I heard is still going strong. But I think that it is impossible to rank the comprehensibility of a complex technical document by the length of words used, as opposed to the way in which the sentences are constructed. The Commentary certainly generated a lot of reader comment, though — as was the intention.
Juicy Studio is so named because it is run by someone called Gez Lemon (great name). It is a site that aims to promote "best practice for web developers in a fast moving industry" and has lots of articles about things like accessibility guidelines for Web 2.0 and Greasemonkey scripts. I think my archiving mission is too low level for them, unfortunately, as it looks like a very nice site. I ran the site through the readability test and it came out with a Gunning-Fog index of 10.5, slightly lower than Petrona. Which just goes to prove my point, as I cannot understand very much of what is on Juicy Studio even though I have at least 10.5 years of "schooling". No disrespect to them, it is simply that I lack the specialist know-how to understand the details of many of the posts, however few syllables per word are used.
PS Blogger spell check, a rudimentary beast, wanted to replace Greasemonkey with gruesomeness.