The appropriate (and inappropriate) use of query operators and their effect on Web search results

In previous work, we showed that the use of Boolean and other operators in queries to Web search engines has little impact on the quality of the results retrieved. This earlier study used 100 queries containing operators selected from a search engine query log. The operators were removed from the queries, and both query versions (with and without operators) were submitted to three popular search engines. There was no significant difference in number of relevant results retrieved in the top 10 items. In this work, we revisit the queries used in this earlier study to examine the manner in which the operators were used. At that time the reason for the relatively low impact of the query operators was not addressed in detail. For each query, the operator used was classified based upon semantic appropriateness and anticipated impact. Most query operators were used in a semantically appropriate manner. This finding suggests that the reason for the relatively low impact of operators on retrieval results was not inappropriate or incorrect use of the operators.