Psychometrics: what is it and what does it do?

Psychology is the science that studies the mind and mental processes. However, these processes are not directly observable by humans and are not easily quantifiable. It can be observed that a person acts in an extrovert manner, but it is not easy to determine to what extent he is.

For this reason, it has become necessary to design different mechanisms and ways of measuring psychic characteristics. The development of these methods, their application, the analysis of these data and the study of their reliability and validity are the object of study of psychometry. Next, we will talk about this area of ​​psychology.

    Psychometry as a measure of the psyche

    Psychometrics is understood as the discipline which is responsible for the quantitative measurement of mental processes and capacities.

    In this way, a numerical value can be assigned to specific characteristics and events, allowing for comparison and contrast with other people or with certain criteria that can be used to establish and test theories and hypotheses about the functioning of the mind. Through psychometry it is possible to quantify and operationalize the psyche, Having largely enabled the development of psychology as a science.

    Since the mind is something which is not directly observable, it is necessary to use elements which can indicate the aspect to be dealt with and the degree to which it is possessed, using observable indicators such as behavior or l recording of the physiological activity of the mind.

    Generally speaking, we can say that psychometry uses statistical computation and analysis of results in order to acquire information about a particular construct (which speaks of a psychological aspect) through an element of measurement that has already been created. .

      What does he understand?

      As we have seen, psychometry is the branch of psychology that is responsible for measuring specific aspects of the mind. This implies on the one hand the establishment of a theory capable of relating mental characteristics to measurable elements, on the other hand the creation of measurement scales, and finally the development of mechanisms and instruments allowing this measurement.

      1. The creation of the theory

      As for the first aspect, psychometry establishes the possibility of measuring unobservable constructions from elements that can be used to indicate them, such as the characteristics of the pipe. It also develops and establishes how they can be observed and, from different data, tries to establish what these indicators can be.

      2. The stairs

      The creation of stairs or scaling is another of the basic elements that psychometrics is responsible for. These scales make it possible to assign concrete values ​​to the variables analyzed., So that they can become operational and work with them. This involves making a specific variable quantifiable.

      3. Measuring instruments

      The third and last of these aspects is the creation, from the scales previously developed in order to quantify a specific variable, of instruments allowing this measurement.

      Clear examples of them are psychological tests. In this elaboration, we must take into account the fact that it is necessary to seek objectivity, consistency, the ability to discriminate between subjects, and that they are valid and reliable.

      Some relevant concepts

      As a discipline for measuring the unobservable from the observable, psychometry must take into account several concepts for this measurement to be correct and representative. Some of the most relevant concepts are as follows.

      1. Correlation

      The concept of correlation refers to the existence of a kind of link between two variables, This makes the changes in one of them coincide with the variations in the second, although this does not guarantee that the cause-consequence relationship.

      2. Variance and standard deviation

      Variance is the degree to which scores on a test or on the same variable they can even disperse. Standard deviation refers to the dispersion of scores from the mean.

      3. Reliability

      Reliability refers to the extent to which an item or item used to measure a characteristic does not produce errors, Obtain consistent results with different measurements of the same characteristic in the same subject and in the same context.

      4. Validity

      Validity is the degree to which the items we use to measure measure what needs to be measured. There are several types of validity, such as construction, content or ecology.

      A little history

      The history of psychology is closely linked to the measurement of the characteristics and abilities of individuals. Psychology as a science would not emerge until the first psychology lab was established at the hands of Wilhelm Wundt, who would begin to perform experiments in which he attempted to measure reaction times and he would take into account the subjective aspects through the introspection method.

      However, it is believed that the birth of psychometry dates back to the mid-19th century, when Francis Galton would begin work on establishing mechanisms to measure the existence of individual differences between individuals.

      Galton would use mechanisms focused on the measurement of physiological elements, his studies being limited to basic processes. But through his studies, fundamental concepts in psychometry have emerged, as principles of correlation between variables and regression, Which will finally be formalized by Karl Pearson, his student.

      The first psychological tests

      Cattell IDEARIA for the first time the concept of mental testing, applying it to the measurement of sensory capacities, but it would not be until Alfred Binet that scales of measurement of intellectual capacities would begin to develop. Binet, with his assistant Théodore Simon, created the first intelligence scale based on functional criteria.

      Later, over time, various types of ladders would be made, some used even in the military (like Army Alpha and Army Beta, used to classify soldiers based on their intelligence level). later too an attempt would be made to take into account the presence of possible cultural biases in the face of a correct analysis of mental capacity.

      Spearman would interpret Pearson’s correlation, Indicating that the presence of a correlation between the variables indicates the presence of a common element. On this basis, he would eventually generate his theory on the G factor of intelligence.

      further developments

      Some of the main authors who enabled the development of psychometrics were mainly the cited Galton, Binet, Pearson and Spearman, although many authors are said to have played a key role in this discipline.

      Spearman would develop the classic theory of tests according to which scores obtained on tests they had to be compared to the reference group in order to be able to make sense of them, although this limits their reliability and validity to the possibility of modifying the results according to the person with whom the comparison is made.

      Over time, other theories would emerge, like item response theory, Which would seek to combat this limitation, by proposing the test as a means of measuring the level of a subject in a given trait by interpreting it on the basis of statistical probability. Over time, other tests such as aptitude or personality would emerge.

        Some applications and usefulness of psychometry

        Psychometrics is a discipline of particular importance for psychology, as it allows for the operation of different mental processes and for making measurements, setting criteria, making comparisons and even to develop explanatory and predictive models. In addition, it allows you to relate variables and help establish the existence of relationships between them.

        All of this is needed in very different areas, As for example in the following.

        1. Clinical psychology

        The various psychological assessment tests and measures are of great importance in clinical practice. Being able to make measurements about mental characteristics or states allows us to visualize and give us an idea of ​​the condition and severity of the subject, As well as the prioritization of certain aspects during the treatment according to the characteristics of the patient.

          2. Neuropsychology

          Psychological and neuropsychological tests and assessments they give us clues as to how a subject’s mental capacities compare to an established criterion, to the population average or to his own state in previous measurements.

          3. Development assessment

          Throughout our life cycle, we develop our abilities in a certain way. The presence of alterations in this development it can be detected thanks to various procedures carried out thanks to psychometry, making it possible to anticipate and treat dysfunctional elements that make it difficult for the person to adapt to the environment.

          4. Capacity assessment

          Personality characteristics, abilities and skills are some of the many items that the possibility of measurement has arisen from instruments made through psychometrics.

          5. Human resources

          Determining a person’s ability to cope with a particular job is not an easy task. Hiring or not hiring an individual he must take into account his level of ability and his mental state in order to be able to detect the level of suitability for the place and the company.

          This assessment is carried out by interviews with the candidates, as well as by psychometric tests which reflect their level of ability in different aspects.

          6. Research

          Psychology is a constantly evolving science. Research is essential in order to achieve a better understanding of the psyche and reality. Establishing relationships between different situations and / or stimuli and / or generating opposable data are key aspects of this process, for which psychometrics is essential as it is the basis for the creation of measurement methods.

          On the other hand, psychometrics carries an implicit discussion of the extent to which the way in which hypotheses are operationalized in concrete measurement tools and variables is reasonable or not, and what are the epistemological limits.

          Methodological issues

          Psychometry does not provide us with tools allowing us to grasp a completely objective image of the psychological predispositions of the subjects studied. There are many limitations associated with psychometric methods and tools.

          For example, a common problem is that the context in which the psychological tests are taken influences the behavior of the subjects studied. Something as simple as dislike or dislike of passing an assessment tool can skew the results, as well as the nerves to the need to do something you are not used to (fill in several sheets with evidence that measures intelligence, for example).

          On another side, these personality tests based on self-assessment they do not exactly measure the behavioral patterns that characterize these personality patterns, but rather the way in which individuals perceive themselves. In other words, between what we want to study and the data obtained, there is an introspection filter: we must stop to think about their actions, and propose an interpretation. This is not ideal, although assuming that most of the subjects studied tend to answer honestly, it can help to get closer to their personality, habits, etc.

          Bibliographical references:

          • Borsboom, D. (2005). Measuring the Mind: Conceptual Questions in Contemporary Psychometry. Cambridge: Cambridge University Press.
          • Beriot, D. and Exiga, A. (1970). Proof: the abuse of psychotechnics, Paris, Dunod Actualité.
          • Embretson, SE and Reise, SP (2000). Item response theory for psychologists. Mahwah, NJ: Erlbaum.
          • Humphreys, LG (1987). Psychometric considerations in assessing differences in intraspecies intelligence. Behav Brain Sci. 10 (4): 668-669.
          • Kaplan, RM and Saccuzzo, DP (2010). Psychological tests: principles, applications and problems. (8th edition). Belmont, CA: Wadsworth, Cengage Learning.
          • Michell, J. (1997). Quantitative science and definition of measurement in psychology. British Journal of Psychology. 88 (3): 355-383.

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