Alternate Forms Reliability - A method of reliability that determines the degree to which two forms (such as Form A and Form B) of the same test are consistent. Researchers administer both forms to a sample of participants and correlate the scores.

Concurrent Validity - A form of criterion-related validity that refers to the degree that the actual test results are corresponding to the expected results. 

Content Validity -This type of validity refers to the competence of a test to measure the behavior that it initially was designed to measure.

Convergent Validation - An assessment highly correlates with another assessment that measures the same concept.

Construct Validity -This type of validity refers to the adequacy of the operational definition of the test in relation to the hypothesis.  In other words, the design and procedures of a test should be applicable to the original intended hypothesis.

Correlation - The simultaneous change in value of two numerically valued random variables. Correlation Coefficient = r = a value between .00 (no relationship) and 1.00 (a perfect relationship).

Criterion-Related Validity - Also known as instrumental validity, is used to demonstrate the accuracy of a measure or procedure by comparing it with another measure or procedure, which has already been demonstrated valid (a standard or criterion). There are two types: Concurrent validity and Predictive validity.

Discriminant Validation - As assessment does not highly correlate with another assessment that measures an unrelated concept.

Factor Analysis - A statistical technique used to simplify the number of components in a set of data. A researcher names the simplified components accordingly to their characteristics. 

Face Validity - This is NOT true validity.  It is a judgment as to whether the "appearance" of the test looks official to the person taking it.

Frequency Distribution - The systematic arrangement of scores on a measure to reflect how frequently each value on the measure occurred

Inter-Scorer Reliability - The degree of agreement between two or more scorers, judgers, or raters. 

Internal Consistency - The extent to which all items on a test measure the variable or construct.

Mean - The arithmetic average of the scores (Population Mean = µ; Sample Mean =  ̅x)

Mode - Most frequently occurring score

Median - Exact middle value of a distribution of scores arranging the scores from least to greatest.

Normal Distribution Curve - A symmetrical, mathematically defined, bell-shaped frequency distribution

Predictive Validity - How well scores on an assessment reliability predict future performance of the concept that was measured.

Range - The spread between the highest and lowest scores.

Reliability - The extent to which a test or measuring tool is consistent and replicable in its measurements. 

Standardization - Administrating carefully constructed tests to a large, representative sample of people under standard conditions for the purpose of determining norms.

Standard Deviation - A measure of spread within a distribution (the square root of the variance). The most popular and most reliable measure of variability. However, the more skewed the distribution, the more error there will be in the standard deviation because of its reliance of the mean. Standard Deviation = σ; Sample Standard Deviation = S_x

Split-Half Reliability - Is an internal consistency approach in which the scores from a single test are divided into two equal parts and correlated.

Test-Retest Reliability - A method of establishing a correlation coefficient is determined by comparing the scores of the same measuring device administered to the same people on two different occasions. Comparing test results over time allows the test developer to see how stable the test is over time.

Validity - The extent to which a test or measuring tool accurately measures what it was intended to measure.