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Bull Med Libr Assoc. 1980 January; 68(1): 53–57.
PMCID: PMC226414

Random time sampling with self-observation for library cost studies: unit costs of reference questions.


The working time of reference librarians was sampled using random alarm devices and a structured checklist of mutually exclusive categories of reference questions. An average wage rate was applied to the unit time reciprocals derived from the resulting percentages. Wage costs for directional questions averaged $1.98; extended reference queries, $4.57. Random time sampling with self-observation gives acceptable reliability at low cost, minimal interference with service operations, and minimal distortion of collected data due to the collection process. It can be carried out by library managers themselves.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Orr RH, Pings VM, Olson EE, Pizer IH. Developing of methodologic tools for planning and managing library services: 3. Standardized inventories of library services. Bull Med Libr Assoc. 1968 Oct;56(4):380–403. [PMC free article] [PubMed]
  • KRONICK DA. VARIETIES OF INFORMATION REQUESTS IN A MEDICAL LIBRARY. Bull Med Libr Assoc. 1964 Oct;52:652–669. [PMC free article] [PubMed]
  • Divilbiss JL, Self PC. Work analysis by random sampling. Bull Med Libr Assoc. 1978 Jan;66(1):19–23. [PMC free article] [PubMed]

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