Stop Words Leading Practices
When managing stop word rules, consider the following recommendations, and tips:
Avoid adding more than a dozen stop words. Too many stop words can harm since most stop words may still convey some meaning and provide syntactical information used by the search engine to better match content.
The index assigns a semantic value to every term by taking into account their frequency in the index. Very frequent terms in indexed items are considered to carry less meaning. Consequently, the index already attributes minimal ranking weight for the occurrence of stop words in search results. It is thus recommended to add stop word rules only for specific use cases.
If for a specific implementation you expect a high number of long natural language queries, consider using the
partialMatchparameter in your search interface as an alternative to adding all possible stop words. Using this search interface option, you can define a minimum number of keywords to be found in a search result before this search result is returned (see Partial Match). This way, the index favors the most important keywords and stop words become optional.
Add stop words only when needed and always perform tests to ensure your stop words do not negatively impact the search experience in cases other than the one you are trying to improve (see Testing a Stop Word Relevance).