Page Site Advanced 7 of Edited by: Neil J. Keywords : domain. Buy in print. Origins and Definitions. Looks like you do not have access to this content. Entries Per Page:. Methods Map Research Methods. Explore the Methods Map. For example, Figure 5. For example, there are ways to split a set of 10 items into two sets of five. Many behavioural measures involve significant judgment on the part of an observer or a rater. Inter-rater reliability is the extent to which different observers are consistent in their judgments.
Validity is the extent to which the scores from a measure represent the variable they are intended to. But how do researchers make this judgment? We have already considered one factor that they take into account—reliability. When a measure has good test-retest reliability and internal consistency, researchers should be more confident that the scores represent what they are supposed to.
There has to be more to it, however, because a measure can be extremely reliable but have no validity whatsoever. Although this measure would have extremely good test-retest reliability, it would have absolutely no validity.
Here we consider three basic kinds: face validity, content validity, and criterion validity. Most people would expect a self-esteem questionnaire to include items about whether they see themselves as a person of worth and whether they think they have good qualities.
So a questionnaire that included these kinds of items would have good face validity. The finger-length method of measuring self-esteem, on the other hand, seems to have nothing to do with self-esteem and therefore has poor face validity. Although face validity can be assessed quantitatively—for example, by having a large sample of people rate a measure in terms of whether it appears to measure what it is intended to—it is usually assessed informally.
Face validity is at best a very weak kind of evidence that a measurement method is measuring what it is supposed to. It is also the case that many established measures in psychology work quite well despite lacking face validity. The Minnesota Multiphasic Personality Inventory-2 MMPI-2 measures many personality characteristics and disorders by having people decide whether each of over different statements applies to them—where many of the statements do not have any obvious relationship to the construct that they measure.
For example, if a researcher conceptually defines test anxiety as involving both sympathetic nervous system activation leading to nervous feelings and negative thoughts, then his measure of test anxiety should include items about both nervous feelings and negative thoughts. Or consider that attitudes are usually defined as involving thoughts, feelings, and actions toward something.
By this conceptual definition, a person has a positive attitude toward exercise to the extent that he or she thinks positive thoughts about exercising, feels good about exercising, and actually exercises. Like face validity, content validity is not usually assessed quantitatively.
Instead, it is assessed by carefully checking the measurement method against the conceptual definition of the construct. But if it were found that people scored equally well on the exam regardless of their test anxiety scores, then this would cast doubt on the validity of the measure. A criterion can be any variable that one has reason to think should be correlated with the construct being measured, and there will usually be many of them.
For example, one would expect test anxiety scores to be negatively correlated with exam performance and course grades and positively correlated with general anxiety and with blood pressure during an exam.
Or imagine that a researcher develops a new measure of physical risk taking. Criteria can also include other measures of the same construct. For example, one would expect new measures of test anxiety or physical risk taking to be positively correlated with existing measures of the same constructs. This is known as convergent validity. Assessing convergent validity requires collecting data using the measure. Discriminant validity , on the other hand, is the extent to which scores on a measure are not correlated with measures of variables that are conceptually distinct.
For example, self-esteem is a general attitude toward the self that is fairly stable over time. It is not the same as mood, which is how good or bad one happens to be feeling right now. If the new measure of self-esteem were highly correlated with a measure of mood, it could be argued that the new measure is not really measuring self-esteem; it is measuring mood instead.
All these low correlations provide evidence that the measure is reflecting a conceptually distinct construct. Method of assessing internal consistency through splitting the items into two sets and examining the relationship between them. In reference to criterion validity, variables that one would expect to be correlated with the measure. The extent to which scores on a measure are not correlated with measures of variables that are conceptually distinct. Skip to content Chapter 5: Psychological Measurement.
Define reliability, including the different types and how they are assessed. Define validity, including the different types and how they are assessed. Describe the kinds of evidence that would be relevant to assessing the reliability and validity of a particular measure.
Psychological researchers do not simply assume that their measures work. Instead, they conduct research to show that they work.
If they cannot show that they work, they stop using them. There are two distinct criteria by which researchers evaluate their measures: reliability and validity. Reliability is consistency across time test-retest reliability , across items internal consistency , and across researchers interrater reliability. Validity is the extent to which the scores actually represent the variable they are intended to.
Validity is a judgment based on various types of evidence. The reliability and validity of a measure is not established by any single study but by the pattern of results across multiple studies. The assessment of reliability and validity is an ongoing process.
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