issues in psychological research

• what is validity?


  if the study measures what it is claiming to measure
• ways in which studies can lack validity:

  • if there are confounding / extraneous variables affecting measurements
  •  the method of measurement doesn’t measure what it claims to measure
• When assessing the face validity of a test, we…


  look at the test to see if it appears to measure what it claims to measure.
• what is concurrent validity?

  comparing the results obtained to a previous test of the same behaviour, that is known to be valid.
• 2 ways in which a study can lack reliability

  • extraneous variables
  • if the The test or questionnaire to measure the DV is unreliable
• A test has internal reliability if…


  the individual items within a questionnaire are consistent with each other.
• A test has external reliability if…


  the results are consistent every time it is repeated.
• The split-half method tests…


  internal reliability, by splitting the test items in two and comparing the results.
• The test-retest method is…

  a method of testing the external reliability of a questionnaire or test.

  a method in which the researcher gets the same participants take the same questionnaire or test on two separate occasions and compares the results obtained both times.