Federal regulations require the inclusion of several specific types of information in the consent form. The form should be written in the simplest language possible, should be easy to read, and should not include medical jargon. The reading level and comprehension of the intended subject population must also be considered. In general, the language is geared to the sixth- to eighth-grade reading level, although certain populations may require language geared to a fifth- or sixth-grade level. There are many tools to assist investigators in developing the appropriate reading level for the consent form. These include the Flesch-Kincaid Grade Level Index, which assesses reading ease, and the Gunning Fog Index, which assesses sentence structure. Furthermore, it is important to note that computer programs that assess the grade level of written material may not be accurate. If the investigator is still concerned that some of the language may be too advanced for the layperson, a sentence at the end of the consent form, such as “In developing this consent form it was necessary to use several technical words; please ask for an explanation of any that you do not understand,” may be added. Several IRBs have grade school teachers (5th to 8th grade) as members in order to assess the readability of consent forms. It is also worth noting that many prospective subjects cannot read at any level, as many as 25 percent in some cities. This reality underscores the importance of the process rather than the document, and the value of affording subjects the opportunity to take the consent form home for consultation with family or friends prior to signing.
Even if the language of the consent form reflects the appropriate reading level, the investigator may find that the potential subject is having difficulty reading the consent form. If this is the case, then the subject may be functionally illiterate. It is estimated that one-half of adults are unable to understand printed health care material, and approximately 90 million adults have fair to poor literacy. There are several behaviors suggestive of inadequate health literacy skills: (1) asking staff for help; (2) bringing along someone who can read; (3) making excuses, like forgetting one’s glasses; and(4) postponing decision-making, i.e., preferring to take consent forms home (where someone can read). Health literacy may be assessed by the Test of Functional Health Literacy (TOFHLA), which is a thorough test of the subject’s ability to comprehend health material. Unfortunately this test is very time-consuming. The Rapid Estimate of Adult Literacy in Medicine (REALM) is one of the quickest ways to assess literacy, taking only two to three minutes to complete, and it is easy to administer. The link contains a copy of this assessment. Federal regulations [45 CFR 46.117(b)(2)] state that the consent form may be read to the potential subject or a short-form written consent may be utilized (with a witness present) in cases where the subject cannot read the consent form.