1-According to Grove & Burns, extraneous variables “exist in all studies and can interfere with obtaining a clear understanding of the relationships among the study variables” (2011). The amount of influence that extraneous variables can have on dependent variables is through control (Grove & Burns, 2011). When extraneous variables present itself, it can prevent researchers from developing a clear picture of the cause and effect or the ways that each study variables interact with one another. Types of controlled settings that a researcher might conduct their study would be in labs, research or experimental centers, and test units in hospitals or healthcare agencies (Grove & Burns, 2011). Extraneous variables can also be controlled using four different approaches: randomization, matching, using experimental designs, and statical control (“Methods to Control Extraneous Variables,” 2014). Randomization is when treatments are randomly given to the experimental groups. Matching is a technique in which confounding variables such as age, gender, income, etc. are matched into different groups so that each group contains equally distributed variables. The use of experimental designs can completely remove the chances of extraneous variables. 

Grove & Burns. (2011). Understanding nursing research. Retrieved from https://evolve.elsevier.com/cs/product/9781455770601

Methods to Control Extraneous Variables. (2014, July 7). Retrieved from http://www.dissertationcanada.com/blog/methods-to-control-extraneous-variables/

2-Extraneous variables are variables that the researcher sometimes can control and sometimes cannot control that have little to do with the study at hand, but have the potential to have a significant effect upon the study. The extraneous variables sometimes have little effect on a study, or sometimes have the potential to completely throw off a study depending upon their influence on the nature of the study (Street, 1995). A participant’s age or gender could greatly impact the results of a study, in unexpected ways. Controlling for this could mean working with a specific age group of people, or engaging in an all male or all female study so that the extraneous variables do not affect the results of the research. Ultimately researchers need to make correlations between the variables and be certain that the extraneous variables are not impacting the research in a manner that is going to throw off the results significantly (Skelly et al., 2012).

References

Skelly, A., Dettori, J., & Brodt, E. (2012). Assessing bias: the importance of considering confounding. Evidence-Based Spine-Care Journal, 3(01), 9-12. doi:10.1055/s-0031-1298595

Street, D. L. (1995). Controlling extraneous variables in experimental research: a research note. Accounting Education, 4(2), 169-188. doi:10.1080/09639289500000020

3-Extraneous variables are variables that are not being evaluated in a research study, but are simultaneously going to affect that research study. The variables could be something that the researcher knows about, or they could be subtle correlations that the researcher cannot find without examining the information about the participants in the study in greater detail. The variables could be a significant factor in the outcome of the research if they are not properly accounted for (Street, 1995). Limiting the effects of extraneous variables involves first identifying what those variables are. Some of the variables cannot be helped. Others can be controlled for by careful consideration and control mechanisms implemented within the study. This can be done by examining correlations and discovering the correlations that appear to be significant within the context of the study (Skelly et al., 2012). Overall, extraneous variables are an inevitability that a researcher will encounter, but they can be controlled for if the study is evaluated properly.

References

Skelly, A., Dettori, J., & Brodt, E. (2012). Assessing bias: the importance of considering confounding. Evidence-Based Spine-Care Journal, 3(01), 9-12. doi:10.1055/s-0031-1298595

Street, D. L. (1995). Controlling extraneous variables in experimental research: a research note. Accounting Education, 4(2), 169-188. doi:10.1080/09639289500000020