Experimental design research is a research which examines the effect of an independent variable

Experimental design research is a research which examines the effect of an independent variable on the dependent variable, where the independent variable can be manipulated through an intervention. Also, there has to be a randomization of participants, and all confounding variable have to be controlled (Larson & Farber, 2015). The result of the intervention can be seen on the dependent variable. To understand better we can look at the use of chlorohexidine mouthwash on the prevention of ventilator associated pneumonia (VAP) in ICU patients. Chlorohexidine is a dependent variable and this can be manipulated and used in the experimental group while the other group will receive a placebo in order to study the effect of VAP.
Any experimental design is controlled, manipulated and randomized in order to get the best results. The research individuals are chosen randomly, and the independent variables are manipulated in order to see the effect of a treatment on a group of patients.
Non-experimental research
The author of the article published by Minnesota Library in 2010, explains that a non-experimental research is a study where a researcher observes the interaction of a subject. These studies can be conducted when it is unethical to manipulate the independent variable or it is endangering patient’s life. As an example, a researcher tries to investigate the effect of bullying on school age children’s self-esteem. The variable cannot be manipulated, therefore, children who were victim can be selected and their self-esteem can be measured.
Furthermore, in the non-experimental group the variables or subjects cannot control, manipulate or alter but instead the researcher can rely on interpretation, observation or interactions of the subject and come to a conclusion.
Larson, R., & Farber, B. (2015). Elementary statistics: Picturing the world (6th ed.). Boston, MA: Pearson.
Research Methods in Psychology. (2010). Overview of Nonexperimental Research. University of Minnesota Libraries Publishing. Retrieved from https://open.lib.umn.edu/psychologyresearchmethods/chapter/7-1-overview-of-nonexperimental-research/