Which characteristic defines a non-experimental study?

A non-experimental study is characterized primarily by its reliance on observational data rather than active intervention or manipulation by the researcher. This means that in such studies, the researcher observes and collects data on subjects without imposing any treatment or control variables that would affect the outcomes.

In contrast, the inclusion of random assignment to treatment groups or applying an intervention indicates an experimental approach, where researchers actively manage the study to determine causal effects. Non-experimental studies often explore relationships and patterns in existing data, making them valuable for generating hypotheses and understanding phenomena in real-world settings without the constraints of an experimental design. Thus, the defining characteristic of a non-experimental study lies in its observational nature, focusing on data that is collected without manipulation, which is why this particular answer accurately captures its essence.