reliability Flashcards
what is classical test theory?
a measurement theory that defines the conceptual basis of reliability
what does classical test theory do?
specifies procedures for estimating the reliability of scores derived from a psych test or instrument
what is a true score?
a hypothetical score devoid of measurement error
what are observed scores?
the scores we obtain from tests or instruments
what does reliability reflect?
the degree of correspondence between observed and true scores
if there is a discrepancy between true and observed scores, what does this mean?
there is measurement error
what are error scores?
should have a mean of zero
what is low reliability score?
.60
what is the minimum reliability score for beginning stage research?
.70
what is a good level of reliability for research?
.80
what is the necessary reliability score for applied contexts?
.90+
what are parallel tests?
two tests are considered parallel if they are identical to eachother psychometrically, but differ in the actual items that make up each test
what is the assumption of tau-equivalence?
implies that the true scores associated with each test represent the same construct
what is validity?
represents the degree to which the observed scores from a test actually represent the attribute of interest
what does internal consistency reliability involve?
treating different parts or items within the same test as different forms of the test
what are the factors that effect internal consistency?
the degree of consistency between the parts in the test and the length of the test
how does the degree of consistency in the test effect the reliability?
the bigger the correlation, the bigger the reliability
how does the length of the test affect reliability?
the more items, better reliability
what does the spearman brown formula involve?
making an adjustment to the internal consistency reliability estimate to reflect the actual length of the test
what is cronbach’s alpha?
represents the ratio of true score variance to total variance
