Part 1

Application: Reliability and Validity

Basic statistical concepts like reliability and validity are paramount to forensic psychology research. You need to know how reliable and valid any particular research study may be. To do so, you need a good understanding of these concepts as well as others.

As you have learned this week, there are different forms of reliability and validity. Statistical reliability and validity are simply numerical descriptions of the basic concepts of each, which allows the researcher to determine if the instrument gives a consistent measurement (reliability) and if it measures what it claims to measure (validity). Even in the area of treatment, the field of psychology is moving toward "evidence-based therapies." This means that the therapy used must show empirical evidence (reliability and validity) and be of help to those who are treated. Being able to show empirical support for what you do as a forensic psychology professional provides the public and legal system with a way to judge the value of your contribution as a forensic psychology professional.

To prepare for this assignment:

• Review Chapter 5 in your course text, Research Methods for the Behavioral Sciences. Pay particular attention to the definitions of validity andreliability, the various types of validity and reliability, and how measures of each are reported.

• Choose an area of forensic psychology which you find interesting.

• Using the Walden Library, select and review a research study/article that relates to this area and that also addresses validity and reliability.

• Consider whether the validity and reliability, as reported in the research article you selected, are accurate or suspect and why.

The assignment (1-3 pages):

• Briefly describe the research study you selected.

• Explain the type(s) of validity and reliability relevant to this study.

• Explain whether you think the validity and reliability, as reported in the article, are accurate or suspect and why.

• Explain what difference validity and reliability make in the study you selected and why.

Support your Application Assignment with specific references to all resources used in its preparation. You are asked to provide a reference list only for those resources not included in the Learning Resources for this course.

Part 2

Use of Statistics in Research

You might be surprised to learn that many statistical terms are used in everyday life. For example, most people value a friend or coworker who is reliable. What is meant by reliable? Generally speaking, it means that you can count on the friend or coworker to behave in a consistent manner over time. The same is true with reliability as it applies to statistics. For example, a test's reliability is measured by how consistently the test produces the same or similar results over time.

Another statistical concept, validity, can be illustrated in the following example. When you accept a check from a client, you would like for the check to be good. What is meant by good? The check represents the client's willingness to pay for your services and promises that the client has, at minimum, the money in his or her account to pay for the services. Using a term other than good, but meaning the same thing, you want the check to be valid; you want it to represent what it is supposed to represent. Again, the same is true with statistical validity. Statistical validity provides you with a numerical value that represents how accurately something measures what it claims to measure, that the value is good. These are two of the most important statistical concepts that you encounter as you delve into research in forensic psychology.

To prepare for this Discussion:

• Review the article, "How to Read a Research Article." Pay particular attention to the step-by-step description and explanation of areas found in most research.

• Review Chapter 4 in your course text, Research Methods for the Behavioral Sciences. Focus on how conceptual ideas are converted into numbers, measured, and reported.

• Review Appendix B in your course text, Research Methods for the Behavioral Sciences. Pay close attention to how statistical concepts and analyses are used in research.

• Select two statistical concepts you believe are the most important to psychological research, two statistical concepts that you find most interesting, and two statistical concepts you find the most difficult to understand.

• Think about why you find each of these statistical concepts to be most important, most interesting, and most difficult, respectively.

With these thoughts in mind:

Post by Day 4 a brief description of two statistical concepts that you think are most important to psychological research and explain why you think they are important. Then, briefly describe two different statistical concepts that you find most interesting and explain why you find them interesting. Finally, briefly describe, as best you can, two statistical concepts that are most difficult for you to understand and explain your difficulty in understanding them.