Glossary of Assessment Terms

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Grade Norm

The average test score obtained by students classified at a given grade placement.

Guessing Parameter

The probability that a student with very low ability on the trait being measured will answer the item correctly. There is always some chance of guessing the answer to a multiple-choice item, and this probability can vary among items. The guessing parameter enables a model to account for these factors.

Holistic Scoring

A scoring procedure yielding a single score based on overall student performance rather than on an accumulation of points. Holistic scoring uses rubrics to evaluate student performance.

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Intelligence Test

A test that measures the higher intellectual capacities of a person, such as the ability to perceive and understand relationships and the ability to recall associated meaning--in other words, measures the ability to learn.

Interpretation

The act of explaining test scores to students so they understand exactly what each type of score means. For example, a percentile rank refers to the percentage of students in the norm group who fall below a particular point, not the percentage of items answered correctly.

Item

A question or problem on a test.

Item Bias

An item is biased when it systematically measures differently for different ethnic, cultural, regional, or gender groups.

Item Response Theory

The basis of various statistical models for analyzing item and test data. In TABE, the three-parameter model was used in the selection and scaling of items. This model takes into account discrimination, difficulty, and chance level of success (guessing) to describe each item's statistical characteristics.

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K-12 Assessment

An assessment intended primarily for students in elementary and secondary schools. CTB assessments may assess students in the entire K-12 range or just in selected grades, e.g., Grades 2-12 .

Local Norms

Norms that have been obtained from data collected in a limited locale, such as a school system, county, or state. They may be used instead of, or along with, national norms to evaluate student performance.

Location Parameter

A statistic from item response theory that pinpoints the ability level at which an item discriminates, or measures, best.

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Mean

The quotient obtained by dividing the sum of a set of scores by the number of scores; also called "average." Mathematicians call it "arithmetic mean."

Median

The middle score in a set of ranked scores. Equal numbers of ranked scores lie above and below the median. It corresponds to the 50th percentile and the 5th decile.

Mode

The score or value that occurs most frequently in a distribution.

Multiple Measures

Assessments that measure student performance in a variety of ways. Multiple measures may include standardized tests, teacher observations, classroom performance assessments, and portfolios.

Multiple-Choice Item

A question, problem, or statement (called a "stem") which appears on a test, followed by two or more answer choices, called alternatives or response choices. The incorrect choices, called distractors, usually reflect common errors. The examinee's task is to choose from, among the alternatives provided, the best answer to the question posed in the stem. These are also called "selected-response items."

Normal Distribution Curve

A bell-shaped curve representing a theoretical distribution of measurements that is often approximated by a wide variety of actual data. It is often used as a basis for scaling and statistical hypothesis testing and estimation in psychology and education because it approximates the frequency distributions of sets of measurements of human characteristics.

Norm-Referenced Test

A standardized asse