I have two slightly different queries, and am filtering to return only a single unique document. The scores are very slightly different, but in the opposite way from what my (naive) reasoning would have expected.
In the first case the query is text:"j2ee"^2.0, text:"soa"^2.0, text:webservic, text:db2 Note that there are two boosted terms and two unboosted terms. The document, in fact, contains only the terms "db2" and "soa", and note that db2 is an unboosted term. The score is 0.069. The second query is text:"db2"^2.0, text:"j2ee"^2.0, text:"soa"^2.0, text:webservic In this case there are three boosted terms and one unboosted term. Note that now both db2 and soa are "boosted". The score is 0.065, which is slightly smaller, which is the opposite of what I would expect, since I have two boosted terms now instead of just one. Looking at the explanation object, the difference is entirely due to the queryNorm factor (which explain doesn't really "go into"). My next step is to get the Lucene source and try to step through to determine why queryNorm is larger in the first case than the second, but I was wondering if anyone out there can give a simple explanation for why it would differ for these two queries. I use the DefaultSimilarity class. Many thanks in advance-- Donna Donna L. Gresh Services Research, Mathematical Sciences Department IBM T.J. Watson Research Center (914) 945-2472 http://www.research.ibm.com/people/g/donnagresh [EMAIL PROTECTED]
