What is a variable?

A variable is defined as any characteristic or condition that can change or be manipulated in a research study. This is foundational to research methods in psychology, as variables are what researchers measure or manipulate to observe effects and relationships. For example, in a study examining the effects of sleep on cognitive performance, both the amount of sleep (which can be altered) and cognitive performance scores (which can differ based on sleep amounts) are considered variables.

In research, distinguishing between different types of variables—such as independent variables (which are manipulated) and dependent variables (which are measured)—is crucial for designing experiments and interpreting results. By manipulating independent variables and observing changes in dependent variables, researchers can draw conclusions about causal relationships.

The other choices do not accurately capture the essence of a variable in research. A constant factor is not a variable because it does not change; a fixed outcome is not variable either, as it implies a conclusion rather than a characteristic that can change; and an irrelevant measurement does not qualify as a variable since it does not pertain to the research focus. Understanding the concept of a variable is essential for engaging with scientific research and methodologies.