When researchers measure a construct that they assume to be consistent across time, then the scores they obtain should also be consistent across time. Psychologists consider three types of consistency: over time (test-retest reliability), across items (internal consistency), and across different researchers (inter-rater reliability). Reliability refers to the consistency of a measure. In evaluating a measurement method, psychologists consider two general dimensions: reliability and validity. But if it indicated that you had gained 10 pounds, you would rightly conclude that it was broken and either fix it or get rid of it. If at this point your bathroom scale indicated that you had lost 10 pounds, this would make sense and you would continue to use the scale. Your clothes seem to be fitting more loosely, and several friends have asked if you have lost weight. If their research does not demonstrate that a measure works, they stop using it.Īs an informal example, imagine that you have been dieting for a month. Instead, they collect data to demonstrate that they work. Psychologists do not simply assume that their measures work. But how do researchers know that the scores actually represent the characteristic, especially when it is a construct like intelligence, self-esteem, depression, or working memory capacity? The answer is that they conduct research using the measure to confirm that the scores make sense based on their understanding of the construct being measured. Describe the kinds of evidence that would be relevant to assessing the reliability and validity of a particular measure.Īgain, measurement involves assigning scores to individuals so that they represent some characteristic of the individuals.Define validity, including the different types and how they are assessed.Define reliability, including the different types and how they are assessed.

Validity test and reliability test