Tests can be divided into categories according to their intended functions and their sources.

Tests' Functions

One way to classify a test in terms of its functions is by locating it in one of five categories--achievement, aptitude, attitude (opinion), interest, and personality.

Achievement tests are designed to determine how well a person has learned to do something, such as read, spell, calculate, recall historical facts, conduct scientific experiments, analyze social problems, repair automobiles, and more.

Aptitude tests aim at measuring individuals' potential ability to develop a type of skill or knowledge. Such tests are often used to predict people's academic achievement in college, their likely success as a police officer, how suitable individuals are for pilot training, and the like. Measures of intelligence qualify as one variety of aptitude test.

The purpose of attitude or opinion inventories is to estimate how favorably disposed people are toward selected individuals, groups, institutions, values, doctrines, or events. Interest tests--a subclass of attitude inventories--are used to identify people's likes and dislikes regarding kinds of activities and styles of life, such as vocations, fields of academic study, or recreational pursuits.

The term personality tests designates a catch-all class of instruments for appraising such things as people's character traits, personal adjustment, values, sociability, emotional stability, adaptability, or personality structure.

Sources of Tests

The two chief sources of tests are formal test publishers and researchers themselves. Tests issued by publishers are typically of a standardized variety, designed to assess aptitudes or knowledge that people wish to measure. However, when no available published instruments are deemed suitable for a given study, researchers create tests that precisely fit their needs.

Published tests

A great many tests and related assessment instruments have been developed to perform a variety of functions. For example, the Educational Testing Service's test collection library contains well over 16,000 tests and measurement devices gathered from a wide range of sources (Educational Testing Service, 1990).

The most useful descriptions of tests are found in compilations of testing instruments, test publishers' catalogues, library holdings, and journal articles relevant to the aims of the researcher's proposed study.

Probably the two most valuable compilations of test descriptions are those found in the periodic editions of the Mental Measurements Yearbook and The ETS Test Collection Catalog.

For several decades the most helpful guide to standardized tests has been the series of Mental Measurements Yearbooks initiated by Oscar Buros and, since his demise, continued by the Buros Mental Measurements Institute at the University of Nebraska ( Conoley & Kramer, 1989, 1992; Conoley and Impara, 1994, 1995; Kramer & Conoley, 1990; Mitchell, 1985) The yearbooks, which are not necessarily issued annually, contain reviews of achievement, aptitude, intelligence, and personality tests written by analysts who have no connection with the publishers of the tests. Thus, the descriptions and appraisals are likely to be more objective than are the contents of publishers' catalogues, advertising brochures, and manuals that accompany tests. Each new edition of the Buros publications does not repeat reports of tests in earlier editions but describes only the most recent versions of tests. Therefore, if you wish to survey all types of tests from all times, it is necessary to consult all editions.

An even more extensive survey of published tests and related measuring devices is provided in descriptions compiled by the Educational Testing Service's test collection staff. The first ETS Test Collection Catalog (Educational Testing Service, 1990) consists of six volumes (achievement tests and measurement devices; vocational tests and measurement devices; tests for special populations; cognitive aptitude and intelligence tests; attitude tests; and affective measures and personality tests). The second edition ( 1993-1995) is in two volumes (updated achievement tests and measurement devices; vocational tests and measurement devices). Unlike the Mental Measurements Yearbooks, the ETS volumes include no assessments of the strengths and limitations of the listed tests but, rather, confine their treatment to each measuring instrument's name, purpose, contents, types of people for whom the test is intended, and its source. The breadth of coverage is impressive, as suggested by the fact that the volume treating cognitive aptitude and intelligence measures contains descriptions of over 1,300 assessment instruments.

Further sources of test descriptions are the catalogs issued by such publishers as the Educational Testing Service ( Princeton, NJ), Psychological Corporation (555 Academic Court, San Antonio, TX 78204), and Psychological Assessment Resources (P. O. Box 998, Odessa, FL 33556). Catalogs frequently offer more detailed information than that found in the Buros yearbooks and ETS volumes. Publishers' materials also include information about new tests or recent revisions of established instruments that does not appear in the above-mentioned compilations of tests.The appearance of computerized university library catalogs has greatly facilitated the hunt for information about tests. A computer search for names and descriptions of tests can be conducted by the investigator's bringing the library's catalog onto the computer screen, then entering key words to locate pertinent books and journal articles that likely offer assessments of tests or else contain descriptions of studies in which standardized tests have been used. Key terms that serve this purpose can combine (a) the field knowledge, the behavior, or the personal traits that the researcher wishes to assess and (b) a word that either refers to the act of assessing or identifies the time-focus of the assessment.

Researcher-created tests

When none of the available published tests precisely evaluate for the skills or knowledge that a researcher wishes to assess, the researcher is obliged to create a suitable instrument. The following resources are helpful guides to test construction.