Reliability and validity

• What is the difference between reliability and validity?

  Reliability is how consistent research is (can it be repeated and the same result is achieved) and validity is about how accurate it is (does it test what it claims to test)
• What are the types of reliability?

  Test-retest

  Inter-rater
• What is inter-rater reliability?

  When separate clinicians make the same diagnosis on separate occasions from the same information
• What is test-retest reliability?

  The consistency of test scores when the same test is administered to the same individuals on two different occasions, and the same result is achieved
• What is predictive validity?


  If diagnosis leads to successful treatment
• What is descriptive validity?


  Should differ from patients with other disorders
• What is aetiological validity? 


  All should have the same cause for the disorder
• What did Rosenhein do?


  Got participants to check themselves into a mental hospital, saying they had SZ, even though they had nothing wrong with them
• What did Rosenhein find?


  All Ps were detained for over 15 days and normal behaviours were logged as symptoms. This shows perhaps the validity of SZ diagnosis is questionable
• What did Ballie say about diagnosing SZ?


  Every psychiatrist has a differing view of the causes of SZ
• How does SZ have low predictive validity?

  Large range of symptoms
• What does Bentall say about SZ diagnosis?


  It says nothing about cause so it is not valid