Reliability and validity

• What is reliability?

  The consistency of research
• What are the different ways to assess reliability?

  • Inter-rater reliability
  • Test-retest reliability
• What is inter-rater reliability?


  Independently research, observe, then compare results with another researcher
• What is internal reliability?

  The study is consistent in itself
• What is external reliability?

  Can anyone repeat the study and get the same results?
• What is test-retest reliability?


  Repeating the study with the same participants
• How do we improve reliability?

  • Rewrite ambiguous questions on questionnaires
  • Keeping the same interviewer for every reliability
  • Using standardised instructions
  • Fully operationalised behavioural schedules
• What is validity?


  Does it test what it claims to test?
• What is internal validity?


  Can establish cause and effect
• How do we assess internal validity?

  Face validity

  Concurrent validity
• What is face validity?


  Seems like it measures what it claims to measure
• What is concurrent validity?


  Comparing this result with an already established test
• What is external validity?

  Allows you to generalise
• What is ecological validity?

  The extent to which results can be generalised to daily life
• What is population validity?

  The extent to which findings from a study can be generalised to the larger population
• What is is temporal validity?


  Findings are still relevant
• How do we assess external validity?

  Replication

  Meta-analysis
• What is a meta-analysis?

  Aggregating results of many studies of the same topic
• How do we improve validity?

  • Single blind
  • Double blind
  • Standardised instructions and procedures
• What is a single blind trial?

  Participants don’t know the aim of the study
• What are double blind tests?

  Participant and researcher doesn’t know the aims of the study