Monday, December 18, 2006

What Size Body Section Ranks Highest?

This is another one of the controversial questions in many of the SEO (Search Engine Optimization) forums, yet it is very easy to answer for any particular search engine. While popular belief seems to be that pages should be very short (less than 10K) to rank well with the leading search engine, this article conclusively answers that question with a completely different answer.
The methodology is really quite simple for this question. I gathered the results of the queries naturally performed last month by myself and three associates using Yahoo and Google. I then visited each page and wrote down the size of the body section of the page. Those sizes were then tabulated for the top 20 rankings and converted into a normalized ranking correlation.
The resulting number shows each group of body section sizes normalizing into a number between 100 and +100 showing the likelihood of being ranked higher/lower. A value of +100 shows that all 10 rankings were in the proper order to show that pages of the studied size ALWAYS rank HIGHER than pages of another size. A value of 100 shows that all 10 rankings were in the proper order to show that pages of the studied size ALWAYS rank LOWER than pages of another size. Numbers in between show the varying likelihood of rankings proportionally between 100 and +100.
That is the number you see on the Y-axis. On the X-axis, we have groups of page sizes varying from 0 to >100K bytes. Here are the graphs for Yahoo and Google:
http://www.searchenginegeek.com/graphs/dey02.gif
http://www.searchenginegeek.com/graphs/deg02.gif
(Note to Webmasters: Feel free to hot link to the above graphs or even copy them to your own site. Also feel free to delete this note.)
There is an obvious correlation on Google, which shows that body sections of a size between 50K and 60K generally rank much higher than shorter or longer bodies. The Yahoo graph is a bit more erratic, but also shows a nice peak at 60-70K (and another one at 20-30K). This goes against the popular belief that states that shorter pages rank highest. The popular belief is shown to be completely inaccurate with this study.
Notes:
1. For the purposes of this test, the actual body section size in bytes was used. The page was saved to disk and then everything before the body tag and after the end body tag were deleted. The resulting size of the file as reported by the operating system was used. Graphics and any other external references were completely ignored.
2. Over 1,000 queries and over 10,000 sites were examined for this study.
3. There was no exercise to attempt to isolate different keywords. I merely took a random sampling of the queries performed by myself and three associated during the prior month.
Conclusion:
Pages with a body section size between 50K and 70K rank best on the two leading search engines!
This is merely a correlation study, so it cannot be determined from this study whether the leading search engine purposefully entertains this factor or not. The actual factors used may be far distant from the factor we studied, but the end result is that this search engine does, in fact, rank pages between 50K and 60K higher than pages of other sizes.
Copyright 2004 Jon Ricerca

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