FRIDAY, Aug. 13 (HealthDay News) -- The length and complexity of consent forms for people enrolling in clinical trials don't affect the ability of the participants to understand the key points of the study, researchers say.

Some previous studies have suggested that volunteers often fail to comprehend consent forms, which are an ethical cornerstone of research involving people. To address that concern, recent efforts have been made to simplify consent forms.

In this new study, U.S. researchers had volunteers read either a standard or a concise consent form for a low-risk phase 1 study of a marketed drug. The participants' comprehension levels were similar with both forms, and the shorter form didn't appear to harm the quality of informed consent, the study authors found.

The researchers also noted that paid participants had slightly higher comprehension than unpaid participants. This challenges a common assumption that people who are paid to enroll in research may be "blinded by money" and thus ignore important details about the study when reading the consent form.

Another finding was that overall comprehension was not affected by socioeconomic status. This appears to counter claims that people who are socially or financially disadvantaged require special protections when enrolling in clinical trials, according to study authors Ezekiel Emanuel, Christine Grady and colleagues.

The study is published in the July/August issue of the journal IRB: Ethics & Human Research, published by the Hastings Center, a nonprofit bioethics research institute in Garrison, N.Y. Emanuel and Grady are Hastings Center Fellows and bioethics leaders in the federal government.

More information

The U.S. Food and Drug Administration has more about clinical trials.