Derived Score

A test score pertaining to a norm group (such as a percentile, stanine, or grade equivalent) that is an outgrowth of the scale scores. Derived scores are useful descriptors; however, they are not calibrated on an equal-interval scale, so they cannot be added, subtracted, or averaged across test levels the way scale scores can.

Diagnostic Test

A test intended to locate learning difficulties or patterns of error. Such tests yield measures of specific knowledge, skills, or abilities underlying achievement within a broad subject. Thus, they provide a basis for remedial instruction.

Discrimination Parameter

The property that indicates how accurately an item distinguishes between examinees of high ability and those of low ability on the trait being measured. An item that can be answered equally well by examinees of low and high ability does not discriminate well and does not give any information about relative levels of performance.

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Early Childhood Test

An assessment intended for students in kindergarten and grades 1 through 3.

Educational (Instructional) Objective

A statement that defines an intended outcome of instruction. It describes what a successful learner is able to do at the end of the lesson or course, defines the conditions under which the behavior is to occur, and often specifies the criterion or standard of acceptable performance.

Equal-Interval Scale

A scale marked off in units of equal size that is applied to all groups taking a given test, regardless of group characteristics or time of year. Each test yields its own scale. On TABE, for example, scale scores are expressed in numbers ranging from 0 to 999. The continuity of the scale among levels comes from administering special test forms containing items from adjacent test levels to random groups of students. This allows the TABE scales to be calibrated so that a given adult learner is expected to obtain the same scale score regardless of the form or level of the test he or she takes. However, the standard error of measurement associated with that student's score will vary systematically from level to level.

Face Validity

An evaluation of a test based on inspection only.

Floor

The opposite of ceiling, it is the lowest limit of performance that can be measured effectively by a test. Individuals are said to have reached the floor of a test when they perform at the bottom of the range in which the test can make reliable discriminations. If an individual or group scores at the floor of a test, the next lower level of the test, if available, should be administered.

Frequency Distribution

An ordered tabulation of individual scores (or groups of scores) showing the number of persons who obtained each score or placed within each range of scores.

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Grade Equivalent

A score on a scale developed to indicate the school grade (usually measured in months) that corresponds to an average chronological age, mental age, test score, or other characteristic of students. A grade equivalent of 6.4 is interpreted as a score that is average for a group in the fourth month of Grade 6. Grade equivalents do not compose a scale of equal intervals and cannot be added, subtracted, or averaged across test levels the way scale scores can. Here is an excerpt from the "Scale Score to Grade Equivalent Table for TABE 7 & 8."

Scale Score

Grade Equivalent

Reading

Applied Mathematics

Language

800

12.9+

12.9+

12.9+

700

12.0+

12.9+

12.9+

600

11.2

11.6

12.1

500

5.3

5.8

4.4

400