Non-experimental research does not mean nonscientific. Non-experimental research means there is a predictor variable or group of subjects that cannot be manipulated by the experimenter. Typically, this means that other routes must be used to draw conclusions, such as correlation, survey or case study.
There are three broad types of nonexperimental research. Single-variable research focuses on a single variable rather than a relationship between variables. Correlational and quasi-experimentalresearch focus on a statistical relationship but lack manipulation or random assignment.