Unit 5 (from quizlet) Flashcards
based on the idea that a person’s test scores vary from testing to testing because of variables in the testing situation. Given the exact conditions of all the facets in the universe, the exact same test score should be obtained.
Generalizability theory
an estimate of reliability obtained by correlating pairs of scores from the sample people on two different administrations of the same test
Test-retest reliability
The degree of correlation among all items on a scale.
Calculated from a single administration of a single form of a test - useful in assessing homogeneity of the test.
Inter-item consistency
What are IRT models?
Rasch model, dichotomous test items, and polytomous test items
a trait, state, or ability presumed to be ever-changing as a function of situational and cognitive experiences
Dynamic characteristic
The relationship between SEM and the reliability of the test is […];
inverse
the higher the reliability of the test, the lower the SEM
A study examining how generalizable scores from a particular test are if the test is administered in different situations. It examines how much of an impact different facets of the universe have on the test score.
Generalizability study
potential sources of error variance.
The examiner’s physical appearance and demeanor are some factors for consideration here. On an oral examination, some examiners may unwittingly provide clues by emphasizing key words as they pose questions.
Examiner-related variables
a value that according to CTT, genuinely reflects an individual’s ability (or trait) level as measured by a particular test
True score
Sources of error variance
test construction,
administration,
scoring, and/or interpretation
interviews may not have been trained properly, the wording amy have been ambiguous, or the items may have somehow been biased.
methodological error
pressing emotional problems, physical discomfort, lack of sleep, and the effects of drugs or medications. A test taker may make a mistake in entering a test response
Testtaker variables
What does error refer to?
The component of the observed test score that does not have to do with the testtaker’s ability.
all of the factors associated with the process of measuring some variable, other than the variable being measured
Measurement error
if then variance of either variable in a correlational analysis is restricted by the sampling procedure used, then the resulting correlation coefficient tends to be lower
Restriction of range
Could also be used to determine the number of items needed to attain a desired level of reliability
Spearman-Brown formula
assign odd-numbered items to one half of the test and even-numbered items to the other half.
Odd-even reliability
a test containing items of uniform level of difficulty so that, when given generous time limits, all test takers should be able to complete all the test items correctly
Speed test
What problems with CTT?
- all items are presumed to be contributing equally to the score total.
- CTT favors the development of longer rather than shorter tests
It is a useful measure of reliability when it is impractical or undesirable to assess reliability with two tests or to administer a test twice.
Split-half reliability
an index of reliability, a proportion that indicates the ratio between the true score variance and the total variance.
Reliability coefficient
What does the Spearman-Brown formula allow?
a test developer or user to estimate internal consistency reliability from a correlation of two halves of a test.
a source of error measuring a variable that is typically constant or proportionate to what is presumed to be the true value of the variable being measured.
Systematic error
formula for error
X=T+E
(x=observed score, T represents true score, E represents error)
A reliability estimate of a speed test should be based on performance from two independent testing periods using what?
1) test-retest reliability
2) alternate-forms reliability
3) split-half reliability from two separately timed half test.
- if a split-half procedure is used, the obtained reliability coefficient is for half test and should be adjusted using the Spearman-Brown formula
it provides a measure of the precision of an observed test score. It provides an estimate of the amount of error inherent in an observed score or measurement
Standard error of measurement (SEM)
variance from true differences
True variance
- if two scores each contain error such that in each case the true score could be higher or lower, then we would want the two scores to be further apart before we conclude that there is a significant difference between them.
Standard error of the difference