Perceived risk of tamoxifen side effects: A study of the use of absolute frequencies or frequency bands, with or without verbal descriptors

Peter Knapp, Peter H. Gardner, David K. Raynor, Elizabeth Woolf, Brian McMillan

Research output: Contribution to journalArticlepeer-review


Objective: To investigate the effectiveness of presenting medicine side effect risk information in different forms, including that proposed by UK guidelines [[1] Medicines and Healthcare products Regulatory Agency. Always read the leaflet Getting the best information with every medicine. (Report of the Committee on Safety of Medicines Working Group on Patient Information). London: The Stationery Office, 2005.].

Methods: 134 Cancer Research UK (CRUK) website users were recruited via a 'pop-up'. Using a 2 x 2 factorial design, participants were randomly allocated to one of four conditions and asked to: imagine they had to take tamoxifen, estimate the risks of 4 side effects, and indicate a presentation mode preference.

Results: Those presented with absolute frequencies demonstrated greater accuracy in estimating 2 of 4 side effects, and of any side effect occurring, than those presented with frequency bands. Those presented with combined descriptors were more accurate at estimating the risk of pulmonary embolism than those presented with numeric descriptors only.

Conclusion: Absolute frequencies outperform frequency bands when presenting side effect risk information. However, presenting such exact frequencies for every side effect may be much less digestible than all side effects listed under 5 frequency bands. Combined numerical and verbal descriptors may be better than numeric only descriptors when describing infrequent side effects.

Practice implications: Information about side effects should be presented in ways that patients prefer, and which result in most accurate risk estimates. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)267-271
Number of pages5
JournalPatient Education and Counseling
Issue number2
Publication statusPublished - May 2010


  • Risk
  • Side effects
  • Cancer
  • Frequency
  • UK

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