Extraneous variables in research can have affect the different variable in a study. “Controlling extraneous variables enables researchers to determine the effects of an intervention or treatment on study outcomes more accurately”(Grove, Gray & Burns, 2015). Researchers can control the extraneous variables by manipulating the environment, subjects, settings and treatment interventions. Extraneous variables are more involved in Quasi-Experimental type studies. These types of studies have to do with effectiveness of treatment in a partially controlled environment. There are 4 different types of extraneous variables which are demand characteristics, experimenter effects, Participant variable and situational variables. One way researchers can control extraneous variables is through random sampling. When random sampling is done, it does not completely eliminate extraneous variable, it only ensure quality between all groups. If random sampling is not used, the effect the extraneous variable may have on the study results be a lot more of a concern at the end of the study being conducted (Stephanie, 2015).
Grove, S. K., Gray, J., & Burns, N. (2015). Understanding nursing research: Building an evidence-based practice. St. Louis, MO: Elsevier.
Stephanie. (2015, May 10). Extraneous Variable Simple Definition. Retrieved from https://www.statisticshowto.datasciencecentral.com/extraneous-variable/
In order to understand research related to healthcare it is important to understand the terminology. The term variable is used frequently when referring to research. “The simplest definition of a variable is that it is something that takes on different values” (Flannelly, Flannelly, & Jankowski, 2014). Extraneous variables are “variables that exist in all studies and can affect the measurement of study variables and the relationships among these variables” (Grove, Gray, & Burns, 2015). Often in healthcare research the term treatment or intervention are used to describe an independent variable. Outcome is used to describe the dependent variable. “Researchers are concerned about extraneous variables because they can alter or obscure the relationship between the independent variable and the dependent variable, or indicate there is a causal relationship between them when none exists” (Flannelly et al., 2014). One way is to try to control the confounds of the subject such as age and gender. “Another way is to incorporate an extraneous variable as an independent variable in the study design” (Flannelly et al., 2014). Flannelly et al. give the example of grouping participants into age groups. “The third way is to use the person’s age as an independent variable in the statistical analysis” (Flannelly et al., 2014).
Flannelly, L., Flannelly, K., & Jankowski, K. (2014). Independent, dependent, and other variables in healthcare and chaplaincy research. Journal of Health Care Chaplaincy, 20,
Grove, S., Gray, J., & Burns, N. (2015). Understanding nursing research: Building an evidence-based practice. (6th ed.) St. Louis, MO: Saunders.