Reliability

• Internal reliability

  • Measure to which something is consisent within itself
• External reliability

  • Measure of consistency over different times
• How to improve reliability of questionnaires

  • Test re-test
  • Split half measure
• Test-re-test

  • Assess external validity overtime, as study is reconducted
  • Answers can be compared, if produced same scores can be compared via correlation co-efficient (strength)
• Split half measure

  • Assess internal validity
  • Answers divided in half and compared
  • If both halves similar then compared via caculating correlation co-efficient
• Correlation co-efficienct

  • Closer to +1, stronger the strength of the reliability
• Inter-rater

  • The degree to whuch different raters give consisent results