Validity

• Validity concerns legitimacy , whether data collected in a study represents reality
• Face validity concerns the issue of whether a self report measure looks like it is measuring what te researcher intended to measure. Face validity only requires intuitive measurement.
• Content validity involves looking at your method of measurement and deciding whether it measures intended content. You could ask an independent expert on the assessment of stress to evaluate the measurement to be used . Expert might suggest improvements or might approve of the method thus dealing with content validity.
• Concurrent validity involves comparing current method of measuring topic with a previously validated one on the same topic. To do this Ps are given both measures at the same time and then their scores are compared. Expected for people to get similar scores on both measurement thereby confirming concurrent validity
• Construct validity assess the extent test measures target construct in a stress questionnaire we would look at the definition of stress and consider if questions are relevant to construct
• Predictive validity is concerned with whether test predicts what you want it to predict for example you would expect those who score higher in a test for stress to have higher blood pressure.
• If measures of internal validity are low then the items on the questionnaire need to be revised.
• In an experiment internal validity can be affected by poor control of extraneous variables and demand characteristics and researcher bias. In self reports validity may be affected by social desirability bias` or leading questions.
• Internal Validity

  • 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 (mundane realism) and would apply to different places , times or people
• Validity Issues

  1. Researcher Bias
  2. Demand Characteristics
  3. Social Desirability
• • Researcher Bias can be overcome with a double blind procedure this involves neither the researcher collecting data nor the participants involved knowing the true aims of study
  • It also reduces demand characteristics can also be overcome via single blind procedures this involves the participant being unaware after their role is complete
  • Alternatively use of independent groups would reduce these validity issues by giving participants anonymity and confidentiality which also increases validity