Psychometry

Psychometry is the discipline that deals with the set of methods, techniques and theories involved in measuring and quantifying the psychological variables of the human psyche.

Historical basis

Psychological tests come from two different currents, the first from Darwin, Galton and Cattell, where the measurement of individual differences is taken into account; the second stream originates from Herbart, Weber Fechner and Wundt and their similarly constructed psychophysical measurements. From the second group of researchers has come the development of experimental psychology and standardized tests.

Validity and reliability

Psychometrics encompasses the theory and construction of valid and reliable tests, tests, and other measurement procedures. It includes the elaboration and application of statistical procedures that allow to determine if a test or test is valid or not for the measurement of a previously defined psychological variable or behavior.

The contents of psychometrics are articulated, fundamentally, in two large blocks: test theory, which refers to the construction, validation and application of tests, and scaling, which includes methods for the development of psychophysical scales and psychological.

The key concepts of classical test theory are: reliability and validity. A test is "reliable" if it is always measured in the same way, that is, if the application of the instrument gives stable and consistent measurements, while it is "valid" if it really measures the attribute it intends to measure.

Both properties, validity and reliability, admit of mathematical treatment.

Validity

Validity refers to the degree to which the test actually measures the variable or variables it claims to measure. There are different types of validity:

• Content validity: consists of the degree to which a test reflects in a differentiated way the set of specific traits that it intends to measure, within a "U" universe of possible traits.
• Validity of criterion: refers to the degree of effectiveness with which the instrument can predict the variables compared to some external criteria. When the test and criterion are measured at the same time, concurrent validity is spoken. When the criterion is measured after the application of the test, it is a prognostic or predictive validity. Finally, the retrospective validity is when the test is applied after the criterion.
• Validity of construct: many of the variables that study psychology are not directly observable, so they are defined hypothetically in the form of constructs. The construct validity focuses on analyzing the amount of empirical data supported by the measured construct.
• Validity of experts: supposes to submit the measurement of the variable to the analysis of the scientific community, composed of people of proven knowledge and experience in the matter.

Reliability

The reliability refers to the degree of consistency and stability of the scores obtained throughout successive measurement processes with the same instrument, which implies the absence of retest of measurement errors. There are basically two ways to measure it: Fanny

• Test- or correlation coefficient: measure the stability of the scale over time on your individual scores
• Internal consistency or Alpha coefficient of Cronbach: measures the accuracy with which the elements of the scale measure the construct.

Observations

• The total validity of an instrument grows to the extent that it makes the validity of content, the validity of construct and the validity of criterion.

• The reliability of an instrument is a necessary but not sufficient requirement: an instrument can be reliable but not valid. Both characteristics are required.

• Instruments are designed to measure a number of variables, but are developed in a specific language, within a given culture and are validated in population groups belonging to a particular community. The use of instruments in countries other than those in which they have been developed is invalid, so it is necessary not only to develop a version in the language of the country in which they are to be applied, but to validate in population samples according to that country.

Types of tests

• Inventory of BarOn: The questionnaire contains a series of short phrases intended to describe the person on certain occasions. It presents a 5-point rating scale: Rarely or never is my case, rarely is it my case, sometimes it is my case, many times it is my case and almost always it is my case. He seeks to evaluate emotional intelligence.
• Wartegg Design Test: The basic test consists of 8 white paintings within which there are small drawings, you should draw in each picture what you want. It allows us to know the individual's position vis-à-vis certain aspects such as: personality, relationships management, dynamism and vital energy for achieving objectives, using the processes of analysis, association and synthesis, managing anxiety, ethical behavior against values, among others.
• DISC personality test: It consists of 24 groups of four words, one must choose the one with which it is most identified and with which it is less described. It measures the behavior and emotions of people in relation to four dimensions of the personality: Factor D, Dominance, how the person responds to the problems and challenges; factor I, Influence, how he relates to other people and influences them; factor S, Stability, how he responds to the changes and rhythm of the environment; and factor C, Conscientiousness, how he responds to the rules and procedures established by others.
• RAVEN Intelligence Test: It consists in finding the missing piece in a series of shown figures, the purpose is that the evaluated analyze the presented series, and taking into account the horizontal and vertical sequence, you must choose one of the six suggested pieces and fit perfectly in both senses, horizontal and vertical. It is used to measure intellectual capacity, comparing forms and reasoning analogies, regardless of the knowledge gained, therefore provides information on the clarity and understanding capacity of the examiner for intellectual activity. This test forces to launch analogous reasoning, perception and abstraction capacity.