Tuesday, 12th June 2007
Less Than 1% of Results Overlap in Major Search Engine Queries
We don't think there is anything specifically new here except that it's more fuel for the "use (and/or know about) more than one search tool" fire.
A new study (see below), reports only 3.6 percent of the No. 1 ranked non-sponsored search results were the same across all search engines for a given query, down from 7.0 percent in the July 2005 overlap study.
ResourceShelf has been suggesting users taking advantage of more than one general purpose engine since we started. People like Greg Notess have been pointing this out for even longer.
Even if you don't use more than one engine with every search, it's important to have some knowledge of what is and what is not available, what are the strengths and weaknesses of each search tool, etc. This goes for both general web engines and specialty/vertical search tools. In fact, these results also add more fuel to the consideration of vertical search resources and directories (LII.org, IPL, Intute, etc.). In most cases, there is no cost to use these databases, so spending money to acquire them is not an issue. Of course, your time and effort is worth a lot.
A new survey that was commissioned by Dogpile (a meta search engine) and conducted by researchers at Pennsylvania State University and Queensland University of Technology in April 2007.
A similar study was commissioned in 2005 and we posted about it here.
Only 3.6 percent of the No. 1 ranked non-sponsored search results were the same across all search engines for a given query, down from 7.0 percent in the July 2005 overlap study.
Fast Facts from the Survey
First page results on Google, Yahoo, Windows Live (MSN Search) and Ask (Ask Jeeves) overlap less than 1 percent.
Remember, many people do not look beyond the first page of search results. Usually only 10 results. Also factor in users only entering a few "general" search terms, the ambiguity of language, and still for some users, not understanding the differences between sponsored and non-sponsored results.
+ 88.3 percent of total results were unique to one search engine.
+ 8.9 percent of total results were shared by any two search engines.
+ 2.2 percent percent of total results were shared by three search engines.
+ 0.6 percent of total results were shared by the top four search engines.
We like to think of search engine overlap with a "classical" library mindset. Libraries often acquire (for a fee) more than one reference book or electronic database that contain the same data, journal indexing, etc. However, each database or book might offer different features, different ways of indexing, etc. In other words, it's worth the money to offer, know about, and use a variety of tools. No one resource is ideal for each query.
See Also: Direct to the Full Text of the Report (PDF; 26 pages)
Note (1): This study was commissioned by Dogpile, a metasearch engine.
Note (2): Gary is Director of Online Resources at Ask.com