Evaluation of the readability of information sheets for healthy volunteers in phase-I trials

Objective: The aim of the present study was to assess whether information sheets/consent forms submitted to the healthy volunteers of the Clinical Pharmacology Unit (C.P.U.) panel at Glaxo-Wellcome (Verona, Italy) could be considered understandable and to verify the readability and comprehensibility of these documents. Since a volunteer bases his/her decision to take part in a study on the information sheet provided, it is of paramount ethical importance to know whether the sheet conveys all relevant information. In addition, a thorough awareness by the volunteer of the reasons and procedures of the study would increase compliance. Methods: Four indices were used: Flesh-Vacca, Kincaid, Gunning's Fog and Gulpease. All indices rate the degree of difficulty of a text, in the light of the level of schooling of the target population. The documents evaluated were information sheets presented to volunteers. The level of schooling of the population that participated in at least one study was determined: 61.7% of volunteers finished high school and 22.6% had a University degree or diploma; the remaining 15.7% did not finish high school or the datum was not available. Results: The results showed that, when the present study began, all information sheets were "readable" by all volunteers who had at least finished high school. After these preliminary results, some additional linguistic and graphic refinements were adopted in drawing up information sheets. Readability improved to such a degree that all information sheets could be understood by virtually all volunteers. Conclusion: A number of suggestions were identified, which are set out in this paper to assist in the preparation of improved information sheets and a recommendation to value the readability of consent sheets before giving them to the volunteers. The suggestions were split into three categories: communications to the volunteer, text format and text organisation.