Part II: Perform search

II.4.1 Relevance (precision) and completeness (recall)

After each search, you are faced with the task of evaluating the result measured against your needs analysis. If the result is not satisfactory, you must modify your search strategy. You are always on a tightrope walk between finding "too much" and "too little".

  • If all hits of your search are relevant, it is most likely that many titles were not covered by search strategy you have choosen.
  • The more complete the search is, the more irrelevant hits there are.


Gesamtdatenbank = total database

R- relevant, but not found
RG - relevant and found

G - found, but not relevant



Too few hits?
  • Check possible mistakes!
    • Typos?
    • Wrong placeholders, shortcuts, wrong search logic?
    • Default settings considered?
    • Is there a restriction for publication years or languages?
  • Check research method and information tools!
    • All search options used?
    • Index of subject headings checked for additional search terms?
    • Other appropriate information tools?
  • View relevant hits!
    • Other suited keywords or subject headings at disposal?
  • Widen the subject!
    • Add synonyms, generic terms, subterms and related terms to the word list (if necessary, use the thesaurus of a specialist database, e.g. TEMA thesaurus)!
    • Use placeholders more generously!
    • Do not combine all aspects of the topic at once!
Too many hits?
  • Evaluate relevant hits!
    • Are keywords or subject headings included that describe the searched topic more precisely than the terms used so far?
  • Evaluate irrelevant hits!
    • Are there any terms that do not fit the topic? Can the NOT operator be used to exclude such terms?
  • Narrow the subject!
    • Possibly consult the lecturer who has assigned the topic!

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