Psychological testing refers to as a field which is characterized by the use of samples of behavior in to the way of generalizations of every given individual. In psychological testing, however, it is usually not possible to control all the extraneous variables, but the metaphor here is a useful one that forces us on the standardized procedures, on the eliminations of conflicting causes on experimental control and on the generation of hypotheses that can be further investigated. Thus, psychological testing a narrower concept referring to the psychometric aspects of a test.
The actual administration and scoring of the test and the interpretation made of the scores. Tests Test is define as an objective and standardized measure of a sample of behavior. objectivity is at least a theoretically, most aspects of a test such as how the test is scored and how the score is interpreted, are not a function of the subjective decision of a particular examiner but are based on objective criteria. Standardization: that is, no matter who administers scores and interprets the test, there is uniformity of procedure and a sample behavior.
A test is not a psychological X-ray, nor does it necessarily reveal hidden conflicts and for-bidden wishes; it is a sample of a person’s behavior, hopefully a representative sample from which we can draw some inferences and hypotheses. Tests are used for a wide variety of purposes that can be subsumed under more general categories. These categories include classification, self-understanding, program evaluation and scientific inquiry. (Kline, 2000).
Major Categories of Tests Classification Classification involves a decision that a particular person belongs in a certain category, For example, based on test results we may assign a diagnosis to a patient, place a student in the introductory Spanish course rather than the intermediate or advanced course, or certify that a person has met the minimal qualifications to practice medicine. Self-understanding Self-understanding involves using test information as a source of information about oneself. Such information may already be available to the individuals, but not in a formal way.
For example, a student studying electrical engineering her high GRE scores confirm what she already knows, that she has the potential abilities required for graduate work. Program evaluation Program evaluation involves the use of tests to assess the effectiveness of a particular program or course of action. You have probably seen in the newspaper, tables indicating the average achievement test scores for various schools in your geographical area, with the scores often taken, perhaps incorrectly as evidence of the competency level of a particular school.
Program offered by a mental health clinic, or the effectiveness of a new medication. Scientific inquiry If you glance through most professional journals in the social and behavioral sciences, you will find that a large majority of studies use psychological tests to operationally define relevant variables and to translate hypotheses into numerical statements that can be assessed statistically. (Kline, 2000).
Major Users and Uses of these Tests Tests are tools usually used by professionals to make what may possibly be some serious decisions about a client: thus both test and the decision process involves a variety of ethical considerations to make sure that the decisions made are in the best interest of all concerned and that the process is carried out in a professional manner. There are serious concerns on the part of both psychologists and lay people, a about the nature of psychological testing and its potential misuse, as well as demands for increased use of tests. Kline, 2000).
Concepts of Reliability and Validity The word reliability refers to the extent that a measure is relatively free or random error and is consistent in the numbers assigned to objects or events while validity refers to whether the number obtained truly reflects what the user intended to measure. Therefore, validity requires reliability because validity is not a property of the measure, but instead it is to the truthfulness of the inferences that are drawn from the measure.
However, a concept of reliability usually gives the accuracy of a measurement, while the concepts of validity it relates to the truthfulness of a measurement. The concepts of reliability and validity can be explain as when estimating parameters from some data with statistical methods, it is important to understand the uncertainty of parameters. The uncertainty comes from two sources: sampling and measuring the study units. Often the data is a (random) sample from a population. (Hoshmand, 1994).
The first error then comes from collecting the data and generalizing the results to a population level. Another source of error is present when measuring the study units when assessing the quality of the collected and measured data set, we end up with questions: Are we measuring the right thing? How accurate our measurements are? The former question leads us to the concept of validity which is the most important property of measurement. The latter question is related to the concept of reliability.
The concept of reliability and validity has a major impact in the field of psychological testing. this is because that since generalizability theory is for investigating and designing the reliable observations, thus, each has test score, a single true score, single reliability and validity coefficient and belong to one family of parallel observations, but the generalizability theory which serves both may produce error which is due to multiple scores. (Rush, First, & Blacker, 2008).