Evaluating the readability of informed consent forms used in contraceptive clinical trials.

The readability level of informed consent forms used in clinical trials on contraceptives was determined. Three different formulas for measuring readability were used. Some forms received relatively high scores by all three methods. The most common problems associated with high readability scores were the use of 'unfamiliar' words, long words and long sentences. At present all forms used must be readable, using the SMOG formula, at a grade 6 level or less.