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.
Then assess its internal consistency by making a scatterplot to show the split-half correlation even- vs. Discussion: Think back to the last college exam you took and think of the exam as a psychological measure. What construct do you think it was intended to measure? Comment on its face and content validity. What data could you collect to assess its reliability and criterion validity? Cacioppo, J. The need for cognition. Journal of Personality and Social Psychology, 42 , — Hoyle Eds.
The consistency of a measure. Validity refers to whether the study or measuring test is measuring what is claims to measure. Internal validity refers to whether it is exclusively the independent variable causing the change or whether there are confounding variables. External validty refers to how well the laboratory study can be generalised to real life settings.
What is the difference between reliability and validity? Remember, something can have reliability but not validity and validity but not reliability. Answered by Natalie H. Ensure that your method and measurement technique are high quality and targeted to measure exactly what you want to know. They should be thoroughly researched and based on existing knowledge.
For example, to collect data on a personality trait, you could use a standardized questionnaire that is considered reliable and valid. If you develop your own questionnaire, it should be based on established theory or findings of previous studies, and the questions should be carefully and precisely worded. To produce valid generalizable results, clearly define the population you are researching e.
Ensure that you have enough participants and that they are representative of the population. Reliability should be considered throughout the data collection process. Plan your method carefully to make sure you carry out the same steps in the same way for each measurement. This is especially important if multiple researchers are involved. For example, if you are conducting interviews or observations, clearly define how specific behaviours or responses will be counted, and make sure questions are phrased the same way each time.
When you collect your data, keep the circumstances as consistent as possible to reduce the influence of external factors that might create variation in the results. For example, in an experimental setup, make sure all participants are given the same information and tested under the same conditions. Showing that you have taken them into account in planning your research and interpreting the results makes your work more credible and trustworthy.
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APA Citation Generator. Reliability vs validity Reliability Validity What does it tell you? The extent to which the results can be reproduced when the research is repeated under the same conditions.
The extent to which the results really measure what they are supposed to measure. How is it assessed? By checking the consistency of results across time, across different observers, and across parts of the test itself.
By checking how well the results correspond to established theories and other measures of the same concept. How do they relate? A valid measurement is generally reliable: if a test produces accurate results, they should be reproducible.
You measure the temperature of a liquid sample several times under identical conditions. The thermometer displays the same temperature every time, so the results are reliable.
A doctor uses a symptom questionnaire to diagnose a patient with a long-term medical condition. Several different doctors use the same questionnaire with the same patient but give different diagnoses. This indicates that the questionnaire has low reliability as a measure of the condition. If a symptom questionnaire results in a reliable diagnosis when answered at different times and with different doctors, this indicates that it has high validity as a measurement of the medical condition.
The thermometer that you used to test the sample gives reliable results. However, the thermometer has not been calibrated properly, so the result is 2 degrees lower than the true value.
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