Reliability of Selection Measures

1 / 13

# Reliability of Selection Measures - PowerPoint PPT Presentation

Reliability of Selection Measures. Reliability Defined. The degree of dependability, consistency, or stability of scores on measures used in selection. Error of Measurement . Obtained Score True Score Error Score. Errors of Measurement.

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

## PowerPoint Slideshow about 'Reliability of Selection Measures' - saul

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 of Selection Measures

Reliability Defined

The degree of dependability,

consistency, or stability of

scores on measures used in

selection

Error of Measurement

Obtained Score

• True Score
• Error Score
Errors of Measurement

-Physical characteristics = Higher reliability (HR)

-Psychological attributes = Lower reliability (LR)

==================================

• Large amounts of measurement

error = LR

• Small amounts of measurement

Error = HR

Methods of Estimating Reliability
• Examines two sets of measure
• If scores from the two measurements are similar, reliability will be raised
• If scores from the two measurements are dissimilar, reliability will be lowered
Methods of Estimating Reliability
• Statistical procedures calculated reliability coefficients range from 0.00 to 1.00
• Higher the coefficient, the less the measurement error, and the higher the reliability estimate
• Lower the coefficient, the higher the measurement error, and the lower the reliability estimate
Methods of Estimating Reliability

Selecting a method:

• Dependability of data collected today be reflective of the same person in the future
• To what degree do evaluations vary from one another
• Accuracy of scores on measuring the true ability
• Dependability of an assessment of a measure at a given moment
Methods of Estimating Reliability

Test-Retest

Same measure is used to

collect data from the same

person at two different times

• The higher the coefficient, the greater the approximation to the true score: closer to 1.00
• The lower the coefficient, the greater likelihood of error: closer to .00
Methods of Estimating Reliability

Test-Retest – Sources of error

• Memory
• Learning
• “True change”
Methods of Estimating Reliability

Parallel or Equivalent Forms

Does not use the same measure

equivalent versions of the measure

• Each has same number of

questions

• Each has same level of difficulty
• Averages of scores are the same
Methods of Estimating Reliability

Internal Consistency Estimates

How similar are different parts of the measure (e.g. different questions on a test) in what they measure?

• Split-half reliability
• Kuder-Richardson Formula 20
• Coefficient Alpha (α) – most commonly reported
Factors Influencing The Reliability of a Measure
• Method of Estimating Reliability
• Individual Differences Among Respondents
• Length of a Measure
• Test Question Difficulty