Though data analysis occurs after the study has completed a data collection stage, the researcher needs to have in mind what type of analysis will allow the researcher to obtain an answer to a research question. The researcher must understand the purpose of each method of analysis, the characteristics that must be present in the study for the design to be appropriate and any weaknesses of the design that might limit the usefulness of the study results. Only then can the researcher select the appropriate design. Choosing the appropriate design enables the researcher to claim the data that is potential evidence that provides information about the relationship being studied. Notice that it is not the statistical test which tells us that research is valid, rather, it is the research design. Social workers must be aware of and adjust any limitations of their chosen design that may impact the validity of the study.
To prepare for this Discussion, review the handout, A Short Course in Statistics and pages 210“220 in your course text Social Work Evaluation: Enhancing What We Do. If necessary, locate and review online resources concerning internal validity and threats to internal validity. Then, review the Social Work Research: Chi Square case study located in this weeks resources. Consider the confounding variables, that is, factors that might explain the difference between those in the program and those waiting to enter the program.

Post2 to 3 pages) an interpretation of the case studys conclusion that the vocational rehabilitation intervention program may be effective at promoting full-time employment. Describe the factors limiting the internal validity of this study, and explain why those factors limit the ability to draw conclusions regarding cause and effect relationships.
 
Required Readings
Dudley, J. R. (2014). Social work evaluation: Enhancing what we do. (2nd ed.) Chicago, IL: Lyceum Books.
Chapter 9, Is the Intervention Effective? (pp. 226“236: Read from Determining a Causal Relationship to Outcome Evaluations for Practice)
Plummer, S.-B., Makris, S., & Brocksen S. (Eds.). (2014b). Social work case studies: Concentration year. Baltimore, MD: Laureate International Universities Publishing. [Vital Source e-reader].
Read the following section:
Social Work Research: Chi Square (pp. 63“65)
Document: Stocks, J. T. (2010). Statistics for social workers. In B. Thyer (Ed.), The handbook of social work research methods (2nd ed., pp. 75“118). Thousand Oaks, CA: Sage. (PDF)
Copyright 2010 by Sage Publications, Inc.
Reprinted by permission of Sage Publications, Inc. via the Copyright Clearance Center.
Trochim, W. M. K. (2006). Internal validity. Retrieved from http://www.socialresearchmethods.net/kb/intval.php
Be sure to click on all the links in the narrative.