Successive Fractions Narrowing a general search using by adding additional topics. Once the initial search is performed the searcher will then either have a series of useful restrictions to apply or will scan a large number of records to determine what restrictions would be useful.
Successive fractions is a useful approach for searchers who are unfamiliar with the search topic.
You are unfamiliar with the literature on this topic. You examine several of these records . If the number of records found is still to large then you could examine more records from the new set to identify additional restrictions. Suppose you decide to focus on lymphedema in breast cancer patients. After restricting the initial results to those discussing breast cancer or mastectomy, you examine several of the records from this new set.