Internal Validity and External Validity Are Important

¶ … internal validity and external validity are important when designing, implementing, and reviewing empirical research. Internal validity refers to the design of the research and its methodology. Issues like sampling, statistical analyses, robustness of the variables, survey instruments, and researcher bias can impact internal validity. With regards to my research question, internal validity is of the utmost importance. The independent variables in this case include two different types of interventions: bloodless cardiac surgeries and blood transfusions. However, it is important to operationalize these two independent variables so that the researchers are clear on what exactly constitutes a bloodless surgery and a blood transfusion. Moreover, issues like hospital setting must be taken into account as a potentially confounding variable. When, where, and how these procedures are implemented can all have a bearing on the internal validity of the research design.

Likewise, the dependent variables are morbidity and mortality in patients. It is critical to identify the target patient population, and to define mortality and morbidity. For example, it must be established that any morbidity or mortality measured were linked to the independent variables and not to some other factor. How well the researchers keep the variables tight, linking only the independent to the dependent variables, determines internal validity.

External validity is also crucial to the research. The research has no validity if it is not useful for practice. Therefore, there must be a high level of generalizability. A small patient population can interfere with external validity because it is not possible to generalize a study on only a few subjects. Similarly, the ethnicities, ages, and genders of the population sample impacts external validity. The researcher cannot extrapolate the results to the general population when only a particular population type was being sampled. There are other elements that can influence external validity, such as hospital setting and environmental factors.

Whitson, Huddleston, Savik & Shumway (2007) and Whitson, Huddleston, Savik & Shumway (2010) offer quantitative research that is both internally and externally valid. These studies operationalize the definitions of both the independent and dependent variables, so that future research can be replicated. Also, the researchers controlled the sample and the environments in which the research studies took place. By tightening the research, internal validity is ensured. Peer-reviewed journal articles such as this depend on a high degree of internal validity, without which the research could be considered invalid for application. The external validity in these studies is also relatively high, given the large sample sizes.