LECTURE 5

1 / 6

LECTURE 5 - PowerPoint PPT Presentation

LECTURE 5. TRUE SCORE THEORY. True Score Theory. OBJECTIVES: - know basic model, assumptions - know definition of reliability, relation to TST - be able to compute estimates of reliability for: internal consistency test-retest parallel forms. BASIC EQUATION. x =  + e

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

PowerPoint Slideshow about ' LECTURE 5' - ivan

An Image/Link below is provided (as is) to download presentation

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
LECTURE 5

TRUE SCORE THEORY

True Score Theory

OBJECTIVES:

- know basic model, assumptions

- know definition of reliability, relation to TST

- be able to compute estimates of reliability for:

internal consistency

test-retest

parallel forms

BASIC EQUATION
• x =  + e
• x = observed score
•  = true (latent) score: represents the score that would be obtained over many independent administrations of the same item or test
• e = error: difference between y and 
ASSUMPTIONS
•  and e are independent (uncorrelated)
• The equation can hold for an individual i on item j at one occasion k:
• xijk = ijk + eijk (individual)
• x*** = *** + e*** (group)
• combinations (individual across time)
SOME RESULTS
• VAR(X) = VAR() + VAR(e)

2x = 2 + 2e

• Correlation of x and  is the index of reliability:

x = COV(x, )/ x 

=COV(+e, )/ x 

= 2 / x 

=  / x