A database search strategy

A search strategy ensures that a database search will be systematic and comprehensive.

One of the best ways to learn the fundamentals of database searching is to look at an example of a search strategy and see if you can follow the rationale and logic. If you can, it becomes easier to translate the basic principles to your own searches.

Have a look at the search strategy in the table below and work through it line by line to follow the logic.

If the process and terms in this table are unfamiliar to you, please work through the next few pages of the tutorial to learn more about conducting effective database search strategies. You can build a similar search using the ‘Advanced’ search in PubMed.

In [cats with naturally occurring chronic kidney disease] does [a renal prescription diet compared to normal diet] increase the [survival time] of affected cats?
Search number Search terms used Type of search Comments
1 (Cat OR cats) Free-text A free-text search will find ‘cat’ or ‘cats’ anywhere in the bibliographic record (e.g. in the title field, in the journal title, in the abstract, etc.)
2 Feline* Free-text A truncated (*) free-text search will find any words which begin with the root word ‘feline’ anywhere in the bibliographic record. This will find ‘felines’ as well as ‘feline’. You should be careful when using truncation searches though, as a short word will find more search terms, some of which may not be relevant.For example, ‘Cat*’ will find ‘cat’ and ‘cats’, but also ‘cattle’, ‘catalysts’ and ‘catastrophe’.
3 Felis Free-text A free-text search will find ‘felis’ anywhere in the bibliographic record.
4 Cats Subject heading Searching for the subject heading ‘cats’ should find all bibliographic records which are about cats. Some databases allow you to ‘explode’ a search – this will include narrower subject headings in your search and will combine them using OR. For example, doing an exploded search for ‘cats’ will also find ‘kittens’ and ‘feral cats’.
5 1 OR 2 OR 3 OR 4 Combination search using OR This search combines all the searches used to find any records about cats, using the Boolean operator OR. This is a good way of ensuring that your search is comprehensive.
6 Chronic renal failure Free-text A free-text search will find ‘chronic renal failure’ anywhere in the bibliographic record.
7 Chronic renal disease* Free-text A truncated free-text search will find ‘chronic renal disease’ and ‘chronic renal diseases’ anywhere in the bibliographic record.
8 Chronic renal insufficienc* Free-text A truncated free-text search will find ‘chronic renal insufficiency’ and ‘chronic renal insufficiencies’ anywhere in the bibliographic record.
9 Chronic kidney failure Free-text A free-text search will find ‘chronic kidney failure’ anywhere in the bibliographic record.
10 Chronic kidney disease* Free-text A truncated free-text search will find ‘chronic kidney disease’ and ‘chronic kidney diseases’ anywhere in the bibliographic record.
11 Chronic kidney insufficienc* Free-text A truncated free-text search will find ‘chronic kidney insufficiency’ and ‘chronic kidney insufficiencies’ anywhere in the bibliographic record.
12 Renal failure Subject heading Searching for the subject heading ‘renal failure’ should find all bibliographic records which are about renal failure. As with ‘cats’, you can explode your subject heading search.
13 Kidney diseases Subject heading Searching for the subject heading ‘kidney diseases’ should find all bibliographic records which are about kidney disease. As with ‘cats’, you can explode your subject heading search.
14 6 OR 7 OR 8 OR 9 OR 10 OR 11 OR 12 OR 13 Combination search using OR This search combines all the searches used to find any records about chronic kidney disease, using the Boolean operator OR. This is a good way of ensuring that your search is comprehensive.
15 Renal diet* Free-text A truncated free-text search will find ‘renal diet’ and ‘renal diets’ anywhere in the bibliographic record.
16 Kidney diet* Free-text A truncated free-text search will find ‘kidney diet’ and ‘kidney diets’ anywhere in the bibliographic record.
17 Prescription diet* Free-text A truncated free-text search will find ‘prescription diet’ and ‘prescription diets’ anywhere in the bibliographic record.
18 Therapeutic diet* Free-text A truncated free-text search will find ‘therapeutic diet’ and ‘therapeutic diets’ anywhere in the bibliographic record.
19 Renal diets Subject heading Searching for the subject heading ‘renal diets’ should find all bibliographic records which are about renal diets. As with ‘cats’, you can explode your subject heading search.
20 Therapeutic diets Subject heading Searching for the subject heading ‘therapeutic diets’ should find all bibliographic records which are about therapeutic diets. As with ‘cats’, you can explode your subject heading search.
21 15 OR 16 OR 17 OR 18 OR 19 OR 20 Combination search using OR This search combines all the searches used to find any records about diets, using the Boolean operator OR. This is a good way of ensuring that your search is comprehensive.
22 5 AND 14 AND 21 Combination search using AND This search combines the previous combination searches, using the Boolean operator AND. This will now limit results to records about renal diets in cats with chronic kidney disease.