This is a sub-study of a drug development study conducted by Pfizer, Inc. It will evaluate how well people who participate in research studies understand from the study consent form what the purpose of the study is, the risks and benefits of participating, the procedures they will undergo and their right to withdraw from the study before it ends. It will compare the understanding and satisfaction of those who are given a standard consent form with those who are given a simpler, concise consent form and examine how their understanding of the information is affected by the length, complexity, format, and reading level of the document.

People 18 years of age and older who are participating in a Pfizer drug development study and who are able to read and write English may be eligible for this sub-study.

Participants in Pfizer's drug development study who agree to participate in this sub-study are randomized to receive either the standard consent form or the concise consent form. The standard consent consists of a detailed, multiple page consent form. The concise form is simpler, written at a lower reading comprehension level. Both forms contain all of the required elements of informed consent according to federal regulations, and include information needed to make a decision about participating in the study. Each form also contains information regarding participation in this sub-study. The standard group signs the standard consent form; the concise group is given the standard consent after reviewing the concise form and is asked to review and sign it.

After reviewing the consent form for the main study, participants complete a 20-minute questionnaire that includes questions that measure understanding of study information such as its purpose, risks and benefits, compensation schemes, and other information. Additional questions ask about how the participants made the decision to enroll in the study.