In testing a proposed model of any academic field, huge extents of data are collected and analyzed through a proposed or adopted scale by researchers. It is very significant to test the reliability and the construct validity of this scale. This study aims to explore the important strategies or tools that should be followed to achieve a reliable and valid scale. It also aims to study the two concepts in association with scale testing as well as to afford a snapshot of the recent understandings of the reliability and validity of scale tests as expressed in previous research studies. This paper emphasis mainly on the theoretical and practical parts of reliability, and the affiliation between the two perceptions. Seeking to synthesize research results about the construct validity and internal-consistency reliability of items (factors), we focus on the four main measurements: Cronbach’s alpha, inter- item correlation, corrected item – total correlation, and Cronbach’s alpha if item deleted. These measurements would provide researchers with a clear knowledge about purifying the survey’s scale before using it in collecting the data set. This kind of research is required so that a complete understanding of the construct validity and internal – consistency reliability of items is realized.
Keywords: : Scale, Construct, Cronbach’s Alpha, Internal-Consistency, Reliability, validity
