All search engines are not the same and all search engines do not return the same results. Ask each of the big four search engines the same question and you’ll get four very different sets of answers. Well duh…
But just how different are the results? Different Engines, Different Results, published in April by the good folks at Dogpile gives some hard numbers.
Over the set of all returned first page results 88.3% of first page results are unique to the search engine that returned them and only 1.1% of the first page results turn up in all four engines.
This is a great study for ferreting out little nuggets that will astound and amaze the naive searchers. Even the DH who has to listen to me babble on about this stuff and who, being an ubergeek himself, ought to know better thought that there wasn’t much difference in the results of one SE verses another.
Another favorite number is from Figure 2.
Google’s indexing coverage of the “Total Web”(1) is given as 69.6%.
Do the math. Google doesn’t cover 30.1% of the Web.
That said the study is prone to a bit of an apples and oranges confusion. Sometimes they separate out sponsored and non-sponsored results and other times they don’t.(2)
Cum grano salis. Though they credit researchers at Queensland U. and Penn State this research is in aid of a particular commercial venture — Dogpile. (One of my fav agregators, though.)
(1) Actually the term used in the figure “Total Web” is misleading. It should be “Total Visible (to Search Engines) Web” There’s a whole ‘nother web out there that the search engines can’t see. The authors get it right in the text.
(2) For example in Figure 5 they list the percentages of first page results (of those returned by all four SEs) that you would miss if you had only used one SE. (All around 70%.) But they don’t call out sponsored vs. non sponsored results. So what? So… sponsored results can only appear in results pool of the SEs that the sponsors have chosen to pay for. By definition, there are certain results that can not appear in multiple search engines.
(Why is all the good stuff in the footnotes?)
