Informed consent readability: subject understanding of 15 common consent form phrases.

To conduct research ethically, informed consent must be obtained from each subject or a representative. This consent is documented when the patient signs an informed consent form. According to law, the requisite information for consent is to be presented in "language understandable to the subject or the representative." If consent forms are written in language that subjects do not fully understand, there is no guarantee that they know all the information they need to know to make a well-educated decision regarding their involvement in a clinical research study. Many studies have attempted to evaluate whether consent forms comply to this criteria. Study designs commonly use standardized readability scoring l-11 or patient recall tests of information in the consent form. In a pilot study by Mariner and McArdle, readability formulas were shown to be an inadequate measure of consent form comprehension by patients. Results of patient recall tests are difficult to interpret without control groups to compare recall of well-understood information. A different method of evaluation must be used for accurate assessment of consent form readability. Waggoner and Mayo devised a research study that used a questionnaire format to evaluate the comprehension of common words and phrases found in informed consent forms. If subjects cannot understand the words and phrases used in the consent form, they may not be fully informed when they sign the consent. Through their survey, Waggoner and Mayo identified often used consent form terminology that the general population does not appear to understand. 17 Dr. Waggoner's study is more relevant to subject understanding of consent forms than previous research, but the accuracy of the data is limited by the fact that the study population was not restricted to people who had participated in clinical research. This group may have a different knowledge level than the general public. In addition, questions were posed verbally, and some of the questions asked respondents to define words without context. Written presentation of terms within a context similar to a consent form could affect comprehension. We explored this question through written survey research conducted in the summer of 1995.