PO217 Quiz: PO217 QUIZ 2 NOTES
Document Summary
Measurement errors - are differences in the values assigned to observations that are attributable to flaws in the measurement process - measurement errors can be either systematic or random. Systematic errors occur when our indicator is picking up some other property, in addition to the property it is supposed to measure. Random errors are chance fluctuations in the measurement results that do not reflect true differences in the property being measured. Random errors make our measures unreliable and invalid. Systematic errors are no threat to reliability precisely because they are systematic i. e. they consistently affect our measurement results. But a reliable measure is not necessarily valid. Concurrent criterion-related validity simply involves comparing the results with those obtained using another indicator. Construct validity involves relating an indicator to an overall theoretical framework. Based on our theoretical understanding of the concept we want to measure and on previous research, we postulate various relationships between that concept and other specified concepts.
