Which of the following describes any measurable conditions, events, characteristics, or behaviors that are controlled or observed in a study?

• A. Variables
• B. Hypothetical constructs
• C. Operational definitions
• D. Measures

Answer: (A)

Variables. In research, a variable is anything that can take on different values and be observed or manipulated, such as a behavior, mood, score, or environmental condition. This makes them the things you measure and analyze to see how they relate to each other or respond to changes in the study design.

Hypothetical constructs are abstract ideas like intelligence or motivation that aren’t directly observable. They become measurable only when you specify how to measure them, using an operational definition. Operational definitions describe the exact procedures used to measure a variable. Measures are the actual tools or data collected—like tests, questionnaires, or physiological readings. But the broad category that encompasses all such observable or controllable aspects in a study is variables.