Altavista: Required Terms

[*Kate McGraw]

Sarah,
Your message didn't match my own study of Altavista searches so I just 
went and checked. When I entered
+nesbeitt +library +bridgewater
I got a retrieval of 6 hits. It was only when I left out the + signs that 
retrieval went up to 30,000. I didn't try this search with the advanced 
engine but have found in the past that you get the same estimated number 
of hits with the boolean "and" when compared to simple searches using the 
+ on every term. The order of retrieval will be different unless you also 
put the terms in the ranking box on the advanced form.
Don't know why your search didn't work, but you might want to try it again.

Kate McGraw
Librarian / Business, Science and Technology
Enoch Pratt Free Library
Baltimore, MD 21201 USA
kmcgraw at mail.pratt.lib.md.us
http://www.pratt.lib.md.us/pratt/depts/bst/

On Mon, 24 Mar 1997, Sarah Nesbeitt, Maxwell Library wrote:

> I've noticed something odd when performing a simple query in AltaVista -
> specifically when specifying that terms be required in the search results
> by preceding them with a + sign.  The AltaVista help file states that
> terms will be required in search results by using a + before them, or
> removed when preceded by a - (minus sign).  However, search results don't
> bear this out; in fact, it acts as if no sign was placed in front of the terms
> at all.
> 
> Example:  The search "+nesbeitt" retrieves 468 documents.  (I realize these
> numbers aren't exact.)
> 
> The search "+nesbeitt +library" retrieves approximately "3000 documents."
> 
> The search "+nesbeitt +library +bridgewater" retrieves approximately "30000
> documents."   Etc.  You'd think that forcing more required terms would narrow 
> the search, not widen it.
> 
> As far as I can tell, I'm entering search terms correctly according to the
> example they include in the help file.  Does anyone have any idea why this 
> happens?
> 
> The Advanced Query page, in which one includes AND in between the search
> terms, performs the search correctly.
> 
> Am I missing something?
> 
> Sarah
> -------------------------------------------------------------------------------
> Sarah L. Nesbeitt                        
> Reference Librarian                      E-mail: snesbeitt at bridgew.edu
> The Clement C. Maxwell Library                   nesbeitt at alumni.sils.umich.edu
> Bridgewater State College                Voice:  (508) 279-6153
> Bridgewater, MA  02325  USA
> 
>