[Xapian-discuss] Question about synonyms and relevancy results.

[Rusty Conover]

Hi Guys,

Why does the use synonyms decrease relevancy of the returned results?

Running query 'Xapian::Query((Zserendip:(pos=1) AND Zjacket:(pos=2)))'
3 results found
Estimated matches: 3
ID 39896 100% Serendipity Jacket mens
ID 39947 98% Serendipity Hiking Jacket womens
ID 39964 90% Serendipity Jacket womens

But with synonyms the relevancy is decreased.

Running query 'Xapian::Query((Zserendip:(pos=1) AND (Zjacket:(pos=2)  
OR Zcoat:(pos=2) OR Zparka:(pos=2))))'
3 results found
Estimated matches: 3
ID 39947 72% Serendipity Hiking Jacket womens
ID 39896 64% Serendipity Jacket mens
ID 39964 58% Serendipity Jacket womens

Obviously this is because more terms are involved, but is this  
correct, or can it be disabled so that the synonyms count as just one  
term with regards to relevancy?

Normally I set a floor of a certain amount of relevancy before I  
present results to the user, but since synonyms decrease the  
relevancy I may need to change that, but doing that could lead to  
poor results being returned when it may make more sense to say no  
results were found.

Thanks,

Rusty

P.S. Olly, Wellington is a wonderful city that I've had the pleasure  
to visit many times now, I think you'll find it quite nice.