On the contrary, nonexperimental research involves a variable that cannot be manipulated or change. The variable is controlled and has to remain constant. Participants will not be randomly assigned to either the control or treatment group. This type of experiment does not demonstrate a true cause-and-effect relationship but instead, relies on observation and correlation.
For instance, in 2013, New England Journal of Medicine released an article on what was believed to have been an experimental study. The article suggested that Mediterranean diet lowers the chance of heart attack, stroke, and other cardiovascular diseases by 30%. Mediterranean diet has been recommended since for general prevention. However, it was retracted in 2018 after it was reported that 14% of the participants were not randomly assigned to either a control or treatment group. Married couples were put into the same group and even participants from an entire village was placed into a single group. All this was never reported in the paper.
Yu, C. (2018). Experiment and Non-experiment. Retrieved from http://www.creative-wisdom.com/teaching/WBI/doe.shtml
Bonds-Raacke, J.M., & Raacke, J.D. (2014). Nonexperimental Research Methods from Research Methods: Are You Equipped?.Retrieved from https://he.kendallhunt.com/sites/default/files/uploadedFiles/Kendall_Hunt/Content/Higher_Education/Uploads/Bonds_Raacke_Research_2e_Ch4.pdf