EPPP-Test Construction Review Study Guide.
Item Characteristic Curve - CORRECT ANSWER When using item response theory, this is constructed for each item by plotting the proportion of examinees in the tryout sample who answer the item correctly against either the total test score, performance o...
Item Characteristic Curve - CORRECT ANSWER When using item response theory, this is constructed for
each item by plotting the proportion of examinees in the tryout sample who answer the item correctly
against either the total test score, performance on an external criterion, or a mathematically-derived
estimate of a latent ability or trait. The curve provides information on the relationship between an
examinees level on the ability or trait measured by the test and the probability that he/she will respond
to the item correctly.
Item Difficulty - CORRECT ANSWER This is calculated by dividing the number of individuals who
answered the item correctly by the total number of individuals; ranges in value from 0 (very difficult
question) to 1.0 (very easy item). In general, an item difficulty index of .50 is preferred because it
maximizes differentiation between individuals with high and low ability and helps ensure a high
reliability coefficient.
Item Discrimination - CORRECT ANSWER This refers to the extent to which a test item discriminates
(differentiates) between examinees who obtain high versus low scores on the entire test or on an
external criterion. The item discrimination index (D) ranges from -1.0 to +1.0. If all examinees in the
upper group and none in the lower group answered the item correctly, D is +1.0; if none of the
examinees in the upper group and all examinees in the lower group answered the item correctly, D
equal -1.0.
Relevance - CORRECT ANSWER In test construction, this refers to the extent to which test items
contribute to achieving the stated goals of testing.
Alternate Forms Reliability - CORRECT ANSWER Method for estimating a test's reliability that entails
administering two forms of the test to the same group of examinees and correlating the two sets of
scores. Forms can be administered at about the same time (coefficient of equivalence) or at different
times (coefficient of equivalence and stability). Considered by some experts to be the best (most
thorough) method for assessing reliability.
Classical Test Theory - CORRECT ANSWER Theory of measurement that regards observed variability in
test scores as reflecting two components: true differences between examinees on the attributes
, measured by the test and the effects of measurement (random) error. Reliability is a measure of true
score variability.
Kappa Statistic - CORRECT ANSWER A correlation coefficient used to assess inter-rater reliability.
Reliability/Reliability Coefficient - CORRECT ANSWER This refers to the consistency of a test scores i.e.,
the extend to which a test measures an attribute without being affected by random fluctuations
(measurement error) that produce the inconsistencies over time, across items, or over different forms.
Methods for establishing this include test-retest, alternative forms, split-half, coefficient alpha, and
inter-rater. Most produce a reliability coefficient, which is interpreted directly as a measure of true score
variability - e.g., a reliability of .80 indicates that 80% of variability in test scores is true score variability.
Split-Half Reliability - CORRECT ANSWER This is a method for assessing internal consistency reliability
and involves "splitting" the test in half and correlating examinees' scores on the tow halves of the test.
Spearman Brown Formula - CORRECT ANSWER This is usually used to correct split-half reliability
coefficients, which estimates what the test's reliability would be if it were based on the full length of the
test.
Standard Error of Measurement/Confidence Interval - CORRECT ANSWER An index of measurement
error. Used to construct a confidence interval around an examinee's obtained test score. Its magnitude
depends on two factors: the test's standard deviation and reliability coefficient.
Test-Retest Reliability - CORRECT ANSWER A method for assessing reliability that involves administering
the same test to the same group of examinees on two different occasions and correlating the two sets of
scores. Yields a coefficient of stability.
Coefficient Alpha/KR-20 - CORRECT ANSWER Method for assessing internal consistency reliability that
provides an index of average inter-item consistency. Kuder-Richardson Formula 20 (KR-20) can be used
as a substitute for coefficient alpha when test items are scored dichotomously.
Construct Validity/Convergent and Discriminant - CORRECT ANSWER The extent to which a test
measures the hypothetical trait (construct) it is intended to measure. Methods for establishing construct
validity including correlating test scores with scores on measures that do and do not measure the same
trait (convergent and discriminant validity); conducting a factor analysis to assess the test's factorial
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