Type Of Research Design And Its Impact On Validity
Introduction
Extraneous variables include all those other variables apart from Independent Variables and Dependent Variables. In this text I look at amongst other issues the need for control of these variables in research as well as the various techniques which can be applied with regard to their control.
Type of research design and its impact on validity
In research, validity means the extent to which the research measures that which it intends to measure. The extent to which we can expect the independent variable to produce the effect observed can be referred to as internal validity. External validity simply means the extent to which a researcher can generalize a study’s results beyond the sample. According to Craswell (2003), the research design affects validity virtue of it being used as a basis for the research structure as well as to indicate the contribution of the various research project parts to the research question.My choice of research design to address the topic depends on my use of random assignment to groups. In that respect, the research design which would be most suitable to address this topic is randomized experiment design.There is a very real need to control extraneous variables as they threaten a study’s internal validity. They do this by their tendency to vary alongside the independent variable (Craswell 2003).We can control extraneous variables in three simple ways. One, we must try to ensure that this extraneous variables are kept constant. Two, a researcher can ensure that the influence of extraneous variables are kept constant and lastly, a researcher can ensure that the influence of extraneous variables are distributed randomly. These techniques can also be applied in this study.This control is highly desirable and possible as in this case what we need to do is ensure the use of procedures which limit the co-variance of the extraneous variable with the Independent Variable.
Conclusion
According to Craswell (2003), a study that lacks control will most likely have its findings mixed-up or confused. The threat to internal validity should also motivate the researcher to in one war or the other control these extraneous variables.
References
Craswell, J.W. (2003). Research design: qualitative, quantitative, and mixed method approaches, 2nd Edition. Sage
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