A new sliding control is coming to the Ancestry search function over the next couple of weeks. Located in the upper-left corner of the search results page, it will make it easy to quickly broaden or narrow your search results. Don’t see the search results you were expecting? Simply drag one or more sliders from left to right to quickly modify your results. The slider position shows how closely your search terms should be matched. With all the sliders to the left, your results are matched at the broadest level, and moving one or more sliders to the right will display more exact matches. - See more at: http://blogs.ancestry.com/ancestry/2014/02/24/coming-soon-to-search-more-control-over-your-results/?
This new feature addresses a common problem among users of the large online databases; the proliferation of results that appear to be "false positives." The issue of false positives or results that have the same general terms as used in a search but are the wrong person, give the impression to most users that the search engine does not work. For example, if I search for "John Jones in Pennsylvania" and I get results showing dozens of "John Jones" results but all in other states, they I suspect the program doesn't work. Actually, the search engine is usually doing just what it is supposed to do and give results based on the parameters set by the algorithms employed by the programmers. In this case, there is likely an instruction to the search program to default the search to a larger geographic area if there are no results that match the original search terms.
I realize that my characterization of what happens is highly simplified, but from the standpoint of a user of search engine receiving hundreds or even millions of results which are not what the user is looking for can be disconcerting.
I just checked my Ancestry.com account and do not see the new feature yet, so I will have to wait to evaluate whether or not it addresses the issues of false positives. Stay tuned.