Psychology
Introducing key terms -
Validity

Internal validity — The findings are accurate and the effects on the DV are caused by the IV. Therefore the study measures what it intends to measure (as confounding variables have been controlled and will not affect the results).

External validity — Whether the study paints a true picture of real life behaviours (e.g. if the tasks have mundane realism) and whether the findings would apply to different places, different times, or different people (population validity).

Specific validity issues — Factors that could cause problems with validity such as researcher bias, social desirability bias and demand characteristics.

Researcher bias — Where the researcher either directly or indirectly influences the results of a study, through the process of designing the study or through the way the research is conducted/analysed.

Demand characteristics — A type of confounding variable where participants unconsciously work out the aim and act differently (either through social desirability or the screw you effect).

Social desirability — Where participants give the response that they think will show them in the best possible light. This may mean that they are not a true reflection of their real thoughts/feelings.

Ways of dealing with issues of validity — Improving validity through methods such as double or single blind procedures, or through changing the location/nature of the research tasks to make them more reflective of real life.

Assessing validity* — Methods of checking the internal or external validity of a study.

Concurrent validity* — Validating a measurement by comparing it with an established measurement that has known validity. If similar results occur on both tests, then this new test is valid. If not, then the new test would have to be redesigned and tested.

Construct validity* — The most sophisticated test of validity as it looks at whether the overall results reflect the phenomena as a whole (external validity). Checking the existing definitions of the behaviour being studied and redesigning the test if it measures a different construct.

Content validity* — This objectively checks the method of measuring behaviour is accurate and decides whether it is a fair test that achieves the aims of the study (internal validity). Ask an expert in that specific area of behaviour to check the test is valid.

Predictive validity* — The degree to which a test accurately forecasts a future outcome on a more broadly related topic. Do the findings apply in different and more varied situations? E.g. Do those with high IQ score gain higher grades in exams?

Face validity* — The least sophisticated measure of validity. This validity is simply whether the test appears to measure what it claims to, and hence is subjective. Tests where the purpose is clear, even to naïve respondents, are said to have this validity.