Even at the data collection stage, the social work researcher needs to know what type of data analysis will facilitate an answer to the research question. The researcher should 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 results. Only then can the researcher select the appropriate design. Choosing the appropriate design enables the social work researcher to gather the most relevant information about the relationship being studied. Notice that it is not the statistical test itself that deems the research 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.In this Discussion, you examine a case study involving a quantitative design, determining whether the statistical information supports the programs efficacy and whether there are limiting factors. 1. Post a brief outline of the case study and consider the conclusion that the vocational rehabilitation intervention program may be effective at promoting full-time employment. 2. What statistical information shows whether the program was effective (or not)? 3. Review the factors that limit the internal validity of a study (history, maturation, testing, instrumentation, statistical regression, selection bias, and attrition).4. Select and explain which of these factors might limit the ability to draw conclusions regarding cause-and-effect relationships.
Note from the instructor:
We shift our focus now to research designs of which there are two quantitative and
qualitative. This week we will be evaluating quantitative research which relies primarily on
numbers or measurable data.
Note that it is the research design that determines the validity of the research and not just
the statistical test itself in this case, chi square. In choosing a research design, the
researcher needs to consider any limitations that might impact the validity of the study.
Your DP calls for a thorough evaluation of the research design in the case study:- (a) what
statistical information showed whether the program was effective (or not) and (b) what
factors might have limited the validity of the study (history, maturation, testing,
instrumentation, statistical regression, selection bias, and attrition). Please review the
definition of each carefully to determine what might fit in the case study.
Discussion: Selection of a Statistical Analysis Approach
In this Discussion, you examine a case study involving a quantitative design, determining
whether the statistical information supports the programs efficacy and whether there are limiting
factors.
Post a brief outline of the case study and consider the conclusion that the vocational
rehabilitation intervention program may be effective at promoting full-time employment.
What statistical information shows whether the program was effective (or not)?
Review the factors that limit the internal validity of a study (history, maturation, testing,
instrumentation, statistical regression, selection bias, and attrition).
Select and explain which of these factors might limit the ability to draw conclusions
regarding cause-and-effect relationships.
A Short Course in Statistics
This information was prepared to call your attention to some basic concepts underlying
statistical procedures and to illustrate what types of research questions can be
addressed by different statistical tests. You may not fully understand these tests without
further study. However, you are strongly encouraged to note distinctions related to the
type of measurement used in gathering data and the choice of statistical tests. Feel free
to post questions in the Contact the Instructor section of the course.
Statistical Symbols
µ mu (population mean)
? alpha (degree of error acceptable for incorrectly rejecting the null hypothesis,
probability that results are unlikely to occur by chance)
