validity & reliability

• validity


  refers to whether a measure actually measure what it claims to be measuring
• face validity


  the extent to which a test/ measure appears to asses what it claims to measure at face value
• content validity


  the extent to which a test comprehensively measures the entire concept/ domain it intends to assess
• internal validity


  the extent to which a study can demonstrate a casual relationship between the independent and dependent variables, ruling out confounding variables
• confounding variables


  variables that are. it part of the experiment but may have an impact on the outcome
• external validity


  the extent to which the findings of a study can be generalised to other people, settings or time periods
• ecological validity


  a subtype of external validity that specifically refers to whether the findings of a study can be generalised to real life settings
• concurrent validity


  the extent to which a test correlates well with a currently established measure of the same construct
• temporal validity


  the extent to which the findings of a study or the effectiveness of a measure remain valid over time
• reliability


  a measure of whether something stays the same or is consistent
• internal reliability


  the extent to which the items within a test or measure are consistent with each other and measure the same concept
• external reliability 


  the extent to which a study or measure produces consistent results when repeated under similar conditions
• test re-test reliability 


  the extent to which a test produces to same results when administered to the same participants at different times
• inter - rater reliability

  the extent to which different observers agree in their assessments when measuring the same behaviour