What is a written set of questions answered by a research participant called?

A written set of questions answered by a research participant is known as a questionnaire. This term specifically refers to a structured instrument for gathering information, often used in research to collect data from individuals regarding their opinions, thoughts, feelings, or behaviors. Questionnaires typically consist of various types of questions, including multiple-choice, Likert scale, or open-ended formats, and are designed to be self-administered or administered in a written format.

Surveys are more general terms that encompass various methods of data collection, including questionnaires, but they may also involve interviews and other formats. Interviews, on the other hand, involve direct interaction between the researcher and the participant and can be either structured or unstructured, but they are not typically written. An experiment refers to a research method that involves manipulation of variables to observe outcomes, which is a different concept from the collection of written responses in a questionnaire.