Validity

When I taught psychology, all those years ago, there was an advert on the T.V. for Ronseal Varnish.  The tag-line for the product was that "it does what it says on the tin".  I would tell my students that this could be a way to describe Validity.  Many psychological studies make their participants take a test to measure some aspect of their psychology.  The test is only valid if it measures what it is claiming to measure.  That, in a nut-shell is what you need to know about Validity.

There are several types of validity, and these are listed below:

Face or Content Validity - This involves looking at the tests and assessing whether they look like they are testing what you claim they are testing.  For example, an intelligence test should be made up of questions that measures general intelligence, not general knowledge nor linguistic competence.

Construct Validity -  This involves creating a test that supports the underlying theoretical constructs concerning the variable that you are trying to measure.  For example, if you believe that some psychological characteristics can be inherited then you need  conduct a test with adopted children.  For example carry out a personality test with parents and the same test with the adopted child, and the results should be similar if you have selected the correct test with high construct validity.

Concurrent Validity - This involves comparing a new method or test with an older, established method or test.  This is how they test new drugs that come onto the market.  They will have a measure of how effective an established drug is.  Then they look at the effectiveness of the new drug and see if it is better than the old drug.  It would be unethical to remove the old drug until the new drug has proved its effectiveness.

Predictive Validity - This involves the idea that a psychological test will predict future performance in an individual.  When I was growing up, lots of kids took an exam called the 11-plus.  Those that passed would be placed in Grammar Schools, and those that did not pass would go to Secondary Modern scools.  This exam was supposed to predict life chances.  Those that passed would have a better life than those that failed.  Thankfully, this test is not used as widely as it was, but some coucils still use it.

Ecological Validity - This is the idea that testing someone in a highly controlled environment with a specicically opertionalised test, would mean that the same results should be found, if ecological validity is high, if the same procedure would produce the same results in a different environment.  For example, in the Piliavin study, he looked back at laboratory studies and people behaved in a certain way.  He set up a similar situation in a real-life environment and people did not behave in the same way, e.g. difussion of responsibility was not found in the real life situation but was found in the laboratory studies.  Which one had the greater Ecological Validity?