Informed consent forms for clinical and research imaging procedures: how much do patients understand?

AJR Am J Roentgenol. 1995 Feb;164(2):493-6. doi: 10.2214/ajr.164.2.7839996.


Objective: Informed consent is often obtained in diagnostic radiology, especially for invasive procedures and research studies. However, how much the average patient actually understands of the information contained in these informed consent forms is uncertain. A cross section of the clinical and research consent forms used in diagnostic radiology was evaluated with respect to their readability, that is, how easy or difficult they were to understand.

Materials and methods: The active members of the Association of University Radiologists were solicited to provide copies of their clinical and research informed consent forms. After eliminating duplicates, we digitized the forms and used a computer program to evaluate their readability. Computer readability assessment allows the rapid study of an entire document by a variety of readability formulas (Flesch-Kincaid, Flesch, and Fog).

Results: We received 549 different consent forms from 156 institutions; 265 forms were intended primarily for clinical use and 284 were used primarily for research. Although the clinical consent forms were only 41% as long as those for research, a statistical comparison showed them to be harder to understand (p < 0.005). The mean readability score (years of education needed to understand) for all 265 clinical consent forms was 15 versus 12 for the research forms. The most complex clinical consent forms were those written by hospitals for any type of procedure or operation (the generic surgical or procedure consent form). On average, this type of clinical consent form required at least a college education to understand.

Conclusion: Our results show that most consent forms used in radiology practice are too complex for the average patient to understand. The increased complexity of clinical consent forms, especially the generic surgical or procedure consent forms, as compared with research consent forms, is probably a product of the decreased attention given to the clinical consent forms, the bureaucratic and legal requirements of the clinical forms, and the lack of physician participation in preparing these forms.

MeSH terms

  • Cognition*
  • Diagnostic Imaging / standards*
  • Educational Status
  • Evaluation Studies as Topic
  • Forms and Records Control / standards*
  • Humans
  • Informed Consent* / statistics & numerical data
  • Reading
  • Research
  • Software
  • United States