Margin of Error
Margin of error, sometimes called the confidence interval, is a term used in reporting results in forensic psychology research as well as in the world of polling and elections. For example, when reporting election results, you have probably heard the news media state something like the following: “John Doe has 51% of the vote with a 3-point margin of error.” This means that John Doe probably has 51% of the vote, but the results may not be entirely accurate. He could have any percentage between 48 and 54 (51 plus or minus 3 percentage points) of the vote, but only 95% of the time. The other 5% of the time he could have more than 54% or less than 48% of the vote. Similarly, in a research study, the margin of error refers to how willing and/or likely you are to come to a false conclusion about the results of your research.
To prepare for this Discussion:
- Review Chapter 6 in your course text, Research Methods for the Behavioral Sciences. Pay particular attention to the concept of margin of error and what it represents.
- Using the Walden Library, select a forensic psychology research article of interest to you, and one that uses margin of error in reporting its results.
- Review the study keeping in mind the concept of margin of error and its implications in the study.
- Think about how and why the margin of error impacts the results of the study.
With these thoughts in mind:
Post by Day 4 a brief description of the research article you selected and a brief summation of the sections on methods and results. Explain how the margin of error is reported in the article, and how and why the margin of error impacts the results of the study.
Be sure to support your postings and responses with specific references to the Learning Resources.
- Course Text: Stangor, C. (2015). Research methods for the behavioral sciences (5th ed.). Stamford, CT: Cengage Learning.
- Chapter 6, “Surveys and Sampling”
- Appendix B, “Data Preparation and Univariate Statistics” (pp. 343-361)
- Note: Because of the ever-changing nature of websites such as the one listed below, there is no guarantee that clips or websites will always be available. Hence, the following link is listed as a Optional Resource only. However, it is highly recommended that you view it as it will assist you in completing one or more of your assignments.
- Article: Hart, S., Michie, C., & Cooke, D. (2007). Precision of actuarial risk assessment instruments: Evaluating the `margins of error’ of group v. individual predictions of violence. British Journal of Psychiatry, 190(suppl. 49), 60–65. Retrieved from http://bjp.rcpsych.org/content/190/49/s60.full.pdf+html