Measurement reliability refers to the consistency and stability of a measurement instrument or test across repeated applications. High reliability indicates that the instrument produces similar results under consistent conditions, which is crucial for ensuring the validity of research findings.
Interval measurement is a quantitative research method that allows for the comparison of differences between values, where the intervals between each measurement are equally spaced but there is no true zero point. This method is crucial in fields like psychology and education for assessing attitudes, preferences, and other constructs that require precise differentiation without an absolute starting point.