Week 5: Reliability Measuring instruments have to yield consistent results. It would be a distressing experience if your bathroom scale tells you that you are 65 kilograms one moment and 70 kilograms a minute later. That would be unreliable or inconsistent results because we do not usually expect a weight increase of that magnitude to happen in 60 seconds. Consistency or repeatability is an indispensable characteristic of measuring tools within the physical or psychological sciences. Psychological scales have to ensure that the scores individuals are measured on yield more or less the same figures for the same individuals at different times. Some test-makers re-administer the same scales after a period, and then analyze whether the results are stable. Other test-makers construct two sets of scales measuring the same construct or split the items into two halves, with the first half measuring the same construct as the second half. These two sets or halves are then compared and analyzed for reliability. Be sure to review this week’s resources carefully. You are expected to apply the information from these resources when you prepare your assignments. All resources for this week: Book(s) Fishman, J. A., & Galguera, T. 2003 Introduction to test construction in the social and behavioral sciences: A practical guide. ?Read Chapters A3, A5, & B3 Kline, T. (2005). Psychological testing: A practical approach to design and evaluation. ?Read Chapters 7 and 8 Article/Journal Boyaci, S., Dilek, B., & Atalay, N. (2016). A scale development for 21st century skills of primary school students: A validity and reliability study. ?Read article Website Link(s) Trochim, W. (2006). The research methods knowledge base. ?Review Reliability section Assignment Title Prepare a Reliability Chart Assignment Points 10 Assignment Instructions For this task you will create a chart describing the different methods of establishing the reliability of a psychological instrument. In one column write the method (e.g., test-retest method) and on another column write a brief description for each of the methods. Length: 1 page 4.0. Appraise different approaches to establishing item and instrument reliability. ?
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