PSYC 3003 Methods in Psychological Inquiry

Replication, Generalization, and External Validity

In the Discussion for this week, you addressed one of the threats to the internal validity of a study, that is, confounding variables. This Application Assignment will challenge you to consider possible threats to external validity. Generalization is the extent to which relations among variables in research studies can be demonstrated among a wide variety of people and across different settings. When the results of a research study are generalizable to additional populations and settings, the study demonstrates external validity. However, if a research study is only valid for the particular sample used in the study, then it is not very helpful to the study of psychology.

In the example provided in the Discussion introduction, two online student groups used different study strategies. Now imagine a human resource (HR) manager at a corporation, struggling with the concept of reading comprehension among employees in the workplace setting, wanted to try the new study strategy that the online course instructor had researched. Assume that the online college course instructor had resolved possible issues relating to internal validity and found that the new study strategy was effective at improving reading comprehension. The HR manager presumes that the results of the study with online college students will generalize to her training course at work. However, the replication of the study revealed that, although the new strategy was found to work well for online students, the results did not generalize to the training course in the work setting. Therefore, the original study lacks external validity.

Replications of studies, such as the one in this example, are essential to demonstrate generalization and external validity. This week, you will learn about four types of replication procedures, and you will develop original examples of each procedure with the goal of demonstrating generalization and external validity.

 

Explain the four different types of replications and the purpose of each. Include for each type of replication a brief original psychological study example (i.e., make up your own) that is different for each type of replication (i.e., do not build on the same example). Plan to devote a short paragraph for each.

Briefly explain how replications relate to the concepts of generalization and external validity.

Different types of replication:

The four types of replication are as follows:

1. Exact replication: The goal of exact replication is to repeat previous research study in the same manner as far as possible.Hence, exact replication can be said as an attempt to copy all methods of previous research to determine the consistency in results (Stangor, 2014). One example of exact replication in psychology includes a study has found online CBT technique helps to reduce depressive symptoms in participants from Greece. Another study with same research design and same approach can be replicated again in new setting to determine the consistency of result.
2. Conceptual replication: It is defined as the process where researcher finds the relationship between the same conceptual variable that was studied previously, however the hypothesis is tested with different independent and dependent variables (Stangor, 2014). For example, when assessing impact of environment on increasing anxiety, the first research can use violent videos as stimuli, whereas another research can use violent people around people as stimuli for increase in anxiety.
3. Constructive replication: It is a research method in which same hypothesis as original research is used, however new conditions are added to analyze the changes on previously observed relationship (Stangor, 2014). For example, in a RCT study, one study used aerobic exercise to assess cognitive function in dementia patient and another research can use another exercise or combine two to find the change in cognitive function.
4. Participant replication: This type of replication is done by not changing the design of research, but changing the type of participants for research (Stangor, 2014). For example one study might investigate the effect of aerobic exercise on old people above 50 years, other can do the same with adolescent children.

Relation of replication with the concept of generalization and external validity:

Replication is related to the concept of generalization because if any study is generalizable to real population setting, then it can be easily replicated too. Easy replication of research in target setting will in turn prove the external validity of the study (Tsang, 2014).

References

Stangor, C. (2014). Research methods for the behavioral sciences. Nelson Education.

Tsang, E. W. (2014). Generalizing from research findings: The merits of case studies. International Journal of Management Reviews, 16(4), 369-383.