

It is important to select suitable people to rate a test (e.g. the test is irrelevant and therefore unsuitable.the test is very suitable for that purpose.


Internal validity can be improved by controlling extraneous variables, using standardized instructions, counter balancing, 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 variable. 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. What is internal and external validity in research?
