Reliability and Validity

1 / 10

# Reliability and Validity - PowerPoint PPT Presentation

Reliability and Validity. What is Reliability?. A measure is considered reliable when: there is very little error in the measurement Measurement remains constant under specific conditions. Types of Error. Random Systematic. Effect of Unreliable Measures. Meaningless results

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'Reliability and Validity' - ronli

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### Reliability and Validity

What is Reliability?
• A measure is considered reliable when:
• there is very little error in the measurement
• Measurement remains constant under specific conditions
Types of Error
• Random
• Systematic
Effect of Unreliable Measures
• Meaningless results
• Inappropriate conclusions
Test-Retest Reliability
• Equipment reliability
• Intertester reliability
• Intratester reliability
Interclass Correlation Coefficient
• Measure multiple times
• Assess consistency of measure
• Pearson r
• -1.0 - 1.0
• -1.0 = perfect negative linear relationship
• 0 = no linear relationship
• 1.0 = perfect positive linear relationship
Intraclass Correlation Coefficient
• ICC
• Sensitive to changes in:
• Calibration
• Error from one test to next
• Multiple tester interaction
• Sources of variance
• Between subjects
• Between occasions
• Interaction between subject and test
• Error
Outcomes for the ICC
• Table 9-1
• Table 9-2
• Table 9-3
• Table 9-4
ICC Calculation
• Repeated measures ANOVA
• ICC calculated from
• BMS
• TMS
• EMS
Precision
• Standard error of the measure
• SEM
• As reliability increases SEM decreases