Which instrument measures opinions?

Different research instruments are designed to collect specific types of data. Opinions, attitudes, beliefs, and preferences are subjective and often require direct input from individuals. A questionnaire is a research instrument consisting of a series of questions designed to gather information from respondents. It is highly effective for systematically collecting data on subjective views, allowing individuals to express their opinions, attitudes, and experiences in a structured format.

• Observation: Observation involves watching and recording behavior or phenomena, which can infer opinions but does not directly measure them.
• Test: Tests typically measure knowledge, abilities, or aptitudes, often with objectively correct or incorrect answers, rather than subjective opinions.
• Experiment: Experiments are used to establish cause-and-effect relationships by manipulating variables. While opinions might be collected within an experimental study, an experiment itself is not primarily an instrument for measuring opinions.