Examining the readability of patient-informed consent forms

Marli Terblanche, Lesley Burgess
TREAD Research/Cardiology Unit, Department of Internal Medicine, Tygerberg Hospital and University of Stellenbosch, Parow, South Africa

Primary objective: To investigate the readability of informed consent forms (ICF) used at TREAD Research, a private clinical trial research unit located in Tygerberg Hospital.
Secondary objective: To assess if there is a difference in readability between therapeutic areas, as well as a difference in readability over two time periods.
Methods: The readability of 84 ICFs given to patients at TREAD Research between the years 2000 and 2009 was quantitatively assessed by means of the Flesch–Kincaid Reading Ease, Flesch–Kincaid Grade Level, and Gunning-Fog index.
Results: The mean ± standard deviation (SD) Flesch–Kincaid Reading Ease score for the 84 ICFs was 46.60 ± 5.62 (range 33.2–65.6). The mean ± SD grade level was 12.13 ± 1.8 (range 8.3–14.9) using the Flesch–Kincaid formula and 13.96 ± 1.22 (range 10.3–16.6) using the Gunning-Fog index. Readability at grade level 8 was only found in 1.2% of all the ICFs assessed. No differences were found in readability between therapeutic areas or over the two time periods.
Conclusions: The main finding is that these forms are too complex to be understood by average study participants and their families.

Keywords: Informed consent forms, readability, literacy