Intersearcher and intrasearcher consistency in the selection of search concepts and search terms are considered. The article is based on an empirical study where 32 searchers from four different types of search environments analyzed altogether 12 search requests of four different types in two separate test situations between which two months elapsed. Statistically very significant differences in consistency were found according to the types of search environments and search requests. Consistency was also considered according to the extent of the scope of search concept. At Level I search terms were compared character by character. At Level II different search terms were accepted as the same search concept with a rather simple evaluation of linguistic expressions. At Level III, in addition to Level II, the hierarchical approach of the search request was also controlled. At Level IV different search terms were accepted as the same search concept with a broad interpretation of the search concept. Both intersearcher and intrasearcher consistency grew most immediately after a rather simple evaluation of linguistic expressions.