Per Study.com (2017), Experimental research is when a researcher can manipulate the predictor variable and subjects to identify a cause-and-effect relationship. This typically requires the research to be conducted in a lab, with one group being placed in an experimental group, or the ones being manipulated, while the other is placed in a placebo group, or inert condition or non-manipulated group. A laboratory-based experiment gives a high level of control and reliability.
Per Study.com (2017), Non-experimental research is the label given to a study when a researcher cannot control, manipulate or alter the predictor variable or subjects, but instead, relies on interpretation, observation or interactions to conclude. Typically, this means the non-experimental researcher must rely on correlations, surveys or case studies, and cannot demonstrate a true cause-and-effect relationship. Non-experimental research tends to have a high level of external validity, meaning it can be generalized to a larger population.
The four most commonly used designs for research studies are descriptive, correlational, quasi- experimental, and experimental.”(Grove, Gray & Burns, 2015). Descriptive and correlational designs can be referred to as non-experimental designs because the focus is on examining variables as they naturally occur in environments and not in the implementing of a treatment by the researcher. In experimental design researchers uses random assignment and they manipulate an independent variable around a controlled variable. A true experimental design there must be randomizing, a control group and manipulator of a variable when examining the direct cause or predicted relationships between variables. In a quasi-experiment one of these aspects is missing, typically the random assignment of subjects to groups. (Sousa, Driessnack & Mendes, 2007).
Burns, N.,Gray, J., Grove, S., (2015). Understanding Nursing Research: building an
evidence-based practice. Retrieved from VitalSource Bookshelf Online.
Sousa, V. D., Driessnack,M., & Mendes, I, A. (2007). An overview of research designs relevant to nursing: Part 1: Quantitative research designs. Retrieved from http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-11692007000300022
Study.com (2017). Non-Experimental and Experimental Research: Differences, Advantages & Disadvantages. Retrieved from http://study.com/academy/lesson/non-experimental-and-experimental-research-differences-advantages-disadvantages.html