Comparing Independent, Dependent, and Extraneous Variables: Understanding Levels of Evidence

Compare Independent Variables, Dependent Variables, And Extraneous Variables.

Describe Two Ways That Researchers Attempt To Control Extraneous Variables. Support Your Answer With Peer-Reviewed Articles.

Describe The "Levels Of Evidence" And Provide An Example Of The Type Of Practice Change That Could Result From Each.

Dependent and independent variables are two main variables in an experiment. Independent variable is changed or controlled in the scientific experiment in order to test its effect over dependent variable. In other words, it can be said that a dependent variable is being test or measure in a scientific experiment (Kite, 2017). For example, aim of the paper is to study the affect of carbohydrate intake in regulating the blood glucose level (BGL). The amount of carbohydrate intake is modulated in the research in order to see change in the BGL. Thus, carbohydrate intake is independent variable and BGL is dependent variable. Extraneous variables are any variables that the researchers are not studying intentionally. Like BGL in the not only controlled by diet, weight and other lifestyle habits also play an important role. So apart from carbohydrate intake other factors (co-morbodities) also play an important role in regulating BGL and these co-morbidities are regarded as extraneous variables. Extraneous variables are regarded as the confounding factors promoting that regulate the affect of independent variables over dependent variable. One way to control the affect of extraneous variable is random sampling. Random sampling does not eliminate extraneous variables, it helps to ensure equal distribution of the confounding factors in both the groups (control and experimental groups). Statistical analysis with regulation of the p-value and confidence interval, helps in regulating the affect of the extraneous variable in research results (Abdul-Rahman, Chen & Laidlaw, 2019).

Level 1: Systematic review and meta-analysis of the randomized control trials (RCTs)

Level 2: Evidence gathered from the RCTs

Level 3: Evidence generated through well-designed trials without conducting randomization (quasi experimental)

Level 4: Case control or cohort studies

Level 5: Systematic reviews of qualitative or descriptive study (meta-synthesis)

Level 6: Evidence gathered from single evidence study or qualitative study

Level7: Reports of committees and authorities

For level 1 of evidence or other consistent findings coming from multiple studies of levels 2, 3, 4, strong recommendations are given for the practice change. The healthcare professionals must follow a strong recommendation unless there is certain compelling rational for conducting any alternative approach. The recommendations given by level 2, 3, 4 are not strong recommendations like level 1. Thus in the domain of the practice change related the clinicians must follow the recommendations but must also remain alert about the new information coming out of level 1 of evidence while remaining sensitive to the preferences of the patients. The practice level change for the level 4 and 5 are optional as the results evaluated in such studies can be biased. It is the duty of the clinicians to consider all the options in their decision-making process. They must also stay alert to the newly published evidences that help in balancing the benefit versus harm (Ingham-Broomfield, 2016).

References

Abdul-Rahman, A. L. F. I. E., Chen, M., & Laidlaw, D. H. (2019). A survey of variables used in empirical studies for visualization. Foundations of Data Visualization. Springer.

Burns, P. B., Rohrich, R. J., & Chung, K. C. (2011). The levels of evidence and their role in evidence-based medicine. Plastic and reconstructive surgery, 128(1), 305.

Ingham-Broomfield, J. R. (2016). A nurses' guide to the hierarchy of research designs and evidence. Australian Journal of Advanced Nursing (Online), 33(3), 38.

Kite, M. E. (2017). Linking identification of independent and dependent variables to the goals of science. American Psychological Association (APA). Pp: 76- 81.