Internal reliability Cronbach’s alphaĬronbach's alpha index measures internal consistency, which is, how closely related a set of items are. This analysis has been developed based on the assumption that evaluations may vary according to the rater. The inter-rater analysis measures reliability by comparing each subject's evaluation variability to the total variability involving all subjects. This type of analysis is used for two similar sets of items measuring the same thing, using the same instrument and with the same people. The split-half reliability analysis measures the equivalence between two parts of a test (parallel forms reliability). The internal analysis, allows to determine which elements of your survey are correlated by providing index related to the internal consistency of the scale but also to identify unnecessary elements and therefore to exclude them.
Moreover, they also measure the reliability between two tests administered to the same individuals at two different times. Methods implemented in XLSTAT are used to estimate the internal consistency of a scale by making sure that results to different questions addressing the same phenomenon are coherent. To ensure compatibility with other areas such as quality control where the reliability analysis might also be used, those arrays are labelled observations/variables within XLSTAT. Results of a test collected on a group of individuals are gathered in an individuals/variables array. To the statistician, questions are variables often measured on Likert-type scale (rating answers). In the case of the graphical skill, a question on mental calculus would downgrade the coherence of the scale. The goal of the reliability analysis is to assess the reliability of this scale of measurement, or, in other words, that the construct questions are coherent and measure the same thing. Those elements are gathered within homogeneous constructs also called factors, measurement scales, latent variables or concepts.Īs an illustration, graphical skill might be a factor on which we wish to measure a level on a scale of measurement. We thus define a test made up of questions. The terminology finds its origin in psychometry. Reliability analysis is used in several areas, noticeably in social science.
0 kommentar(er)
