validity and reliability in quantitative studies

For example, individuals who actually take the test would be well placed to judge its face validity.Īlso, people who work with the test could offer their opinion (e.g., employers, university administrators, employers). It is important to select suitable people to rate a test (e.g., questionnaire, interview, IQ test, etc.). the test is irrelevant and, therefore, unsuitable.the test is very suitable for that purpose.the test is extremely suitable for a given purpose.This rater could use a Likert scale to assess face validity. Accordingly, tests wherein the purpose is unclear have low face validity (Nevo, 1985).Ī direct measurement of face validity is obtained by asking people to rate the validity of a test as it appears to them. Tests wherein the purpose is clear, even to naïve respondents, are said to have high face validity. This is the least sophisticated measure of validity.

There are two main categories of validity used to assess the validity of the test (i.e., questionnaire, interview, IQ test, etc.): Content and criterion.įace validity is simply whether the test appears (at face value) to measure what it claims to. Internal validity can be improved by controlling extraneous variables, using standardized instructions, counterbalancing, and eliminating demand characteristics and investigator effects.Įxternal validity refers to the extent to which the results of a study can be generalized to other settings (ecological validity), other people (population validity), and over time (historical validity).Įxternal validity can be improved by setting experiments in a more natural setting and using random sampling to select participants. In other words, there is a causal relationship between the independent and dependent variables. Internal validity refers to whether the effects observed in a study are due to the manipulation of the independent variable and not some other factor. Internal and External Validity In Research

Validity and reliability in quantitative studies