Tuesday, January 22, 2008

Controlled Vocabulary

LC Subject headings, Sears list of subject headings, Canadian Subject Headings, MeSH (Medical subject headings) thesaurus, descriptors, authority control could all be labeled as controlled vocabulary. This eliminates the need for the user to come up with synonyms for search terms

It helps refine ones’ search

Your database may or may not have a controlled vocabulary. But many offer some kind of subject lists to browse or narrow searches. If not, think of other terms you may want to use for an item you are searching: Use 'investment' instead of 'finance', or 'recipe' instead of 'cooking'

It is the lack of controlled vocabulary (selected list of words to search) that casues so much confusion on the web. What you find one day is lost the next.

Stay tuned for more search tools.....

Friday, January 04, 2008

Boolean logic

  • Remember your venn diagrams from yesteryears! That is the basis of Boolean logic.

  • Uses And (+), OR and AND NOT (-)

  • They are spelled in capitals or symbols are used. OR is spelled out

  • AND represents intersection of two sets and will produce smaller results (Note that this AND is not additive. It limits the search)

  • OR represents a combination of two sets and will produce larger results (expands the search)

  • NOT, as the word means, excludes a term you do not want to see in the search. This also produces smaller results

  • What Boolean logic one uses depends on the database and what one is searching for. AND could produce too many results and you might have to use a NOT. Or, NOT might produce too few results and you may have to use AND and OR

Example: Typically, Mandoline NOT Slicer should search for items that are catagorized as Mandolin or Mandoline and omit slicer as a search word. Hence there will be fewer results. (143,000 hits in Google not all of them relevant)
Example: Mandolin OR Slicer will evidently have more results than the previous search. (366,000 hits in Google)
How exactly the results are displayed and what information is retrieved for the user will all depend on the level of sophistication of your database.

(BTW: My new love is for Mandolins that chop or grate your vegetables just perfectly)

More search tools to come.....