Using Cronbach’s alpha to assess the reliability of a new measure of the British Benefit System
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Psychometric tests are a systematic procedure for scoring and evaluating samples according to standards (Urbina, 2004). There are certain issues taken into consideration when creating a new psychometric measure, such as maintaining consistency of results by using identical materials (Howitt and Cramer, 2011). It is also essential to avoid response bias, this is achieved through not using leading questions which suggests expected answers therefore limiting the effect it has on the variability of answers (Howitt and Cramer, 2011).
Hogan and Cannon (2003) defined reliability as the consistency of a measure regardless of what it’s measuring, which may vary, however validity is based on whether a psychological test is measuring what it’s intending to measure. Reliability and validity will be assessed on the measure used in this report, using Cronbach’s alpha. This removes items not measuring what the scale measures thus increasing the consistency of items. Cronbach’s alpha takes all the items into and considers various ways to split them to give an accurate value for the measure’s internal reliability (Howitt and Cramer, 2011).
Reliability and validity are reliant on what is being measured and so they are likely to be affected, depending on context and purpose of the measurement. Taking this into consideration, the aim of this study was to develop an effective measure, with an acceptable internal reliability.
There were 50 participants chosen through opportunity sampling for this study.
Prior to creating the questionnaire (see appendix A) becoming familiar with concepts on British benefit systems was essential. This topic was defined by exploring different areas, different types of benefits and such ...
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...ed a higher value of Cronbach’s alpha if item deleted when compared to others.
The streamlined Cronbach’s alpha suggested that the scale is satisfactory and so it has internal reliability. However the scale may not be valid due to issues with leading questions. Furthermore, it also does not cover certain areas that need to be measured therefore there may also be an issue with the scales content validity which may need to be assessed.
Hogan, T. (2003). Psychological Testing: A Practical Introduction. USA: John Wiley & Sons, Inc.
Howitt, D., & Cramer, D. (2011). Introduction to Research Method in Psychology. England: Pearson Education Limited.
Kline, P. (1986). The Handbook of Test Construction: Introduction to Psychometrics Design. New York: Methuen & Co.
Urbina, S. (2004). Essentials of Psychological Testing. New Jersey: John Wiley & Sons, Inc.