Stemming is a process that reduces keywords to their stem, root or base form when conducting searches. This allows you to conduct searches for words that come from the same stem of the words specified in your search terms, not just the exact words specified in your search terms. A stemmed search for a word finds the exact same terms as well as terms that derive from the same meaning and part of speech as the search term. The stem of a word is not based on spelling. For example, card and cardiac have different stems even though the spelling of cardiac begins with card. On the other hand, running and ran have the same stem, run, even though their spellings are quite different. Stemming allows you to conduct searches that return highly relevant matches that would otherwise be missed.
bidsCanada offers three variations of stemming: Heavy, Medium and Light. Stemming programs are commonly referred to as stemmers. Try experimenting with different stemmers until you receive the best results. Due to the vagaries of the English language, stemming can sometimes be more of an art than science. If in doubt, use the Light stemmer.
Example 1: If you use the Medium stemmer, the keyword supplier returns records that contain the word supply. This does not occur if you use the Light or Heavy stemmers.
Example 2: If you use the Heavy stemmer, the keyword programming returns records that contain the word program. This does not occur if you use the Light and the Medium stemmers.
Example 3: If you use the Medium stemmer, the keyword commissioning returns records that contain the word commission and decommissioning while the Light stemmer does not. The Heavy stemmer returns records that contain the word commission but not the word decommissioning.
Example 4: If you use the Medium stemmer, the keyword application returns records that contain the word applied. This does not occur if you use the Light or Heavy stemmers.
Note: Stemming works on words, not word fragments, so a search for instru will not return the same results as instructional.
For more information on searching effectively please see:
Examples for Searching Effectively.