What type of research method allows a researcher to test a hypothesis under controlled conditions?

An experiment is a research method that enables a researcher to test a hypothesis under controlled conditions. This approach involves manipulating one or more independent variables to observe the effect on a dependent variable, while keeping other factors constant. This level of control allows researchers to establish cause-and-effect relationships and to determine whether the manipulation of the independent variable led to changes in the dependent variable.

In experiments, variables can be carefully controlled and measured, which is essential for validating hypotheses rigorously. This distinguishes experiments from other research methods, such as surveys, field studies, and observations, where the researcher may not have the same level of control over external variables or the environment. In surveys, for example, researchers collect data from participants without altering any conditions, and field studies observe behaviors in natural settings, which can introduce various uncontrolled variables. Observational methods focus on watching and documenting behavior as it occurs naturally, without manipulation or control.

The structured approach of experiments is fundamental in many areas of research, particularly in the sciences, where testing theories is critical to advancing knowledge.