IST:622 Term 4
Week 4 Objectives
MIST 622: Reliability and Validity
Reliability is concerned with the consistency, accuracy and reproducibility of a measure. Validity refers to the degree to which the test measures what it is supposed to measure. We will discuss details of validity next week. A simple graphic understanding of the two can be illustrated by the pictures on this slide.
Concept of Reliability
The reliability concept is based on the assumption that all measurements (or observation) include a true score (T) and an error (e). X = T + e
In educational and psychological measurement reliability of a measure is mostly expressed by correlation coefficients. There are different types of reliability coefficients that take into account different sources of error or inconsistency.
Reliability Coefficients (slide 4)
Standard Error of Measurement (SEM)- used to calculate confidence intervals.
Confidence Intervals- reflects a range of scores that will contain the takers true score with a prescribed probability
Data Collection Methods in Instructional and Performance Technology