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From Erik Hatcher <>
Subject Re: Sorting results by both score and date
Date Fri, 16 Sep 2005 13:54:08 GMT
Tim, check out p. 155 in LIA where we discuss "Sorting by multiple  

However, what you're really after it seems is boosting documents.   
Check out TheServerSide's case study (online or in LIA) - Dion  
discusses how he implemented boosting for more recent documents.  If  
you're indexing documents in ascending date order, perhaps you could  
leverage the document id in such a boosting factor?


On Sep 16, 2005, at 9:43 AM, <>  
<> wrote:

> Hi,
> I'm working in an industry which is fairly time sensitive, and older
> documents are inherently less valuable. I'd like to be able to  
> "weight"
> the score of search results, so that older documents score lower. I
> don't just want to sort by date, though - I'd still like results to be
> ordered by score, just an "adjusted" score.
> I've read the excellent LIA, including the chapter on custom sort
> methods, but from what I can tell that still only implements a sort on
> one field - I really want to be able to sort on a "blend" of fields  
> (one
> of this is the actual document score).
> Could anyone suggest how I could implement this? I considered  
> explicitly
> weighting the documents with a function of their date at index  
> time, but
> this would mean the "weight" of the new documents would have to  
> increase
> exponentially over time, and I suspect things would get messy! (Our
> dataset is around 250k documents, growing by a few thousand a month.)
> Cheers,
> Tim.
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