VALIDITY

• Types of External validity: Ecological Validity: 

  • The extent to which findings from a study can be generalised to other settings / real life
• Types of External validity: Temporal Validity: 

  • The extent to which findings from a study can be generalised to other historical times (high- results are the same then and now, low- results have changed)
• ASSESSING VALIDITY: Face Validity: 

  • Does the test look right? 
  • Done by eyeballing / giving it to an expert to check
• ASSESSING VALIDITY: Concurrent Validity (high= + 0.8 or more)

  • Comparison to another existing test? 
  • Are the results similar? 
  • Are you measuring what you intend to? 
• IMPROVING VALIDITY- EXPERIMENTS:

  • Control group (changes in DV definitely due to IV)
  • Standardised procedures & single / double-blind trials (reduce investigator effects)
• IMPROVING VALIDITY- QUESTIONNAIRES:

  • Assure participants that all data submitted is confidential (answer truthfully)
• IMPROVING VALIDITY- OBSERVATIONS:

  • Operationalise behavioural categories (shouldn’t overlap / be ambiguous)
• ASSESSING INTERNAL VALIDITY- Split half method:

  • Give the same people 2 halves of a questionnaire
  • Compare results
  • 0.8+ or more- reliable