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October 16, 2011
1:00:00 PM - 4:00:00 PM
Room Hall B2 Area L
Informed Consent for Perioperative Research: How Readable are the Forms?
Madhav Swaminathan, M.D., Param Sidhu, Jr., Aman Mahajan, M.D.,Ph.D., Mark Stafford-Smith, M.D.
Duke University, Durham, North Carolina, United States

The Code of Federal Regulations mandates that for informed consent, “The information that is given to the subject or the representative shall be in language understandable to the subject or the representative.”(1) Although not specified in the code, most IRBs consider the use of 7th/8th grade language in their consent forms as standard to enable the use of easy-to-understand language. While readability of consent forms and their consistency over the years has been investigated, studies have been limited to templates rather than actual forms, single institutions, or specific fields of research. We therefore conducted a study to determine the reading grade level of actual informed consent forms used for research in two academic institutions.


With IRB approval, we gathered IRB-approved unselected consent forms from two academic institutions. These included actual approved forms that are being currently used or have been used in studies completed within the last five years. Permission was obtained from the principal investigators of each study. The forms were sourced as electronic documents, and were grouped according to type of study [i.e., observational-intervention (OBS-INT), observational-non-intervention (OBS-NON), evaluation (EVAL), and randomized controlled trial (RCT)]. All forms were subjected to standardized tests for reading level: Flesch-Kincaid, Coleman-Liau, automated readability index (ARI), and Gunning Fog and SMOG tests. Each test generated a score including the grade level for that consent form. Scores were compiled for each consent form and grouped by the four study types. In addition, other data, such as number of words, complex sentences, and syllable count were also assessed for each consent form. Simple statistics were used to describe the reading grade scores for consent forms.


Informed consent forms from two institutions representing 15 different research studies were included in the analysis. There were similar patterns observed for all reading tests for the four study types (table and figure). The mean reading grade level for all consent forms was 11.1. The highest grade level observed was attributable to OBS-NON studies (11.7), while RCT and EVAL studies had the lowest (10.7). Despite the highest reading level, OBS-NON studies had the fewest sentences and complex words on average (table).


Despite the efforts at making informed consent for research more readable for the lay public, these forms operate at a high reading level than desirable for the intended audience. A surprising finding was the higher reading level and greater complexity of consent relating to observational studies compared to RCTs. Studies show that the average North American population is at the 8th grade reading level, while most newspapers operate at a 9th grade reading level. Considering the importance of informed consent by the scientific and regulatory communities, and the public, efforts should be directed towards simplification of language used in informed consent for research.


1. Code of Federal Regulations. Protection of human subjects 2009; Accessed Nov 21, 2009.
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