What distinguishes an experimental study from a non-experimental study?

The defining characteristic that distinguishes an experimental study from a non-experimental study is the presence of random assignment. In experimental studies, researchers randomly assign participants to different groups, typically an experimental group that receives a treatment or intervention and a control group that does not. This randomization helps establish causality by minimizing biases and ensuring that the groups are comparable at the start of the study.

Random assignment is crucial because it allows researchers to infer that any observed effects in the outcome measures can be attributed to the intervention being studied rather than other external factors. In contrast, non-experimental studies do not involve random assignment; they may observe relationships or correlations between variables but cannot definitively establish cause-and-effect relationships due to potential confounding variables.

Other options, such as the use of surveys, the length of the study, or the number of participants, do not inherently differentiate between experimental and non-experimental designs. Surveys can be used in both types of studies, the length can vary based on the research question and design, and the number of participants is dependent on the specific study's requirements rather than its classification as experimental or non-experimental.