Psychometry: what is it and what does it do?

This field of psychology allows us to know our intelligence, personality, habits...

Psychology is the science that studies the mind and mental processes. However, these processes are not directly observable by human beings, nor are they easily quantifiable. We can observe that a person acts in an extroverted manner, but it is not easy to determine to what degree he or she is extroverted.

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 the study of psychical characteristics. is the object of study of psychometry.. Next we will speak about this area of psychology.

Psychometry as a measurement of the psyche

Psychometry is understood as the discipline of quantitative quantitative measurement of mental processes and capacities..

In this way, a numerical value can be assigned to specific characteristics and events, allowing 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. Thanks to psychometrics it is possible to quantify and operationalize the psychicIt has largely permitted the development of psychology as a science.

As the mind is not directly observable, it is necessary to use elements that can indicate the aspect to be treated and the degree to which it is possessed, using observable indicators such as behavior or the recording of physiological activity.

Broadly speaking, we can say that psychometrics uses statistical calculation and analysis of results in order to acquire information about a particular construct (which speaks about some psychological aspect) through a measurement element that has been previously created.

What does it encompass?

As we have seen, psychometrics is the branch of psychology that is responsible for measuring specific aspects of the mind. This involves, on the one hand, establishing a theory that can link mental characteristics with measurable elements, on the other hand, the creation of measurement scales, and finally, the development of mechanisms and instruments that allow such measurement.

1. The creation of the theory

With regard to the first aspect, psychometrics establishes the possibility of measuring unobservable constructs from elements that can be used to indicate them, such as behavioral characteristics. It also elaborates and establishes how they can be observed and, from different data, tries to establish what these indicators may be.

2. The scales

The creation of scales or scaling is another of the basic elements of psychometrics. These scales make it possible to assign concrete values to the variables analyzed, so that they can be operationalized.These scales make it possible to assign concrete values to the variables analyzed, so that they can be operationalized and worked with. It is a matter of making a specific variable quantifiable.

3. Measuring instruments

The third and last of the aforementioned aspects is the creation, from the scales previously elaborated in order to quantify a specific variable, of instruments that allow such measurement.

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

Some relevant concepts

As a discipline that allows the measurement of the unobservable from the observable, psychometry must take into account several concepts in order to ensure that the measurement is correct and representative. Some of the most relevant concepts are the following.

Correlation

The concept of correlation refers to The concept of correlation refers to the existence of some kind of link between two variables.This means that changes in one of them coincide with variations in the second, although this does not ensure that the relationship is one of cause and consequence.

Variance and standard deviation

Variance is the degree to which the scores of a test or of the same variable can become dispersed. can become dispersed. The standard deviation refers to how much the scores are usually expected to be dispersed in relation to the average.

3. Reliability

Reliability refers to the degree to which an item or element used in the measurement of a characteristic does not produce errorsThe reliability of an item or item used in the measurement of a characteristic does not produce errors, obtaining consistent results in different measurements of the same characteristic in the same subject and context.

4. Validity

Validity is understood as the degree to which the item we are using to measure is measuring what we want to measure. is measuring what we want to measure. There are different types of validity, such as construct, content or ecological validity.

A bit of history

The history of psychology is closely linked to that of the measurement of characteristics and capabilities of individuals. Psychology as a science would not appear until the creation of the first psychology laboratory at the hands of Wilhelm Wundt, who would begin to carry out experiments in which he tried to measure reaction times and would take into account the subjective aspects through the method of introspection..

However, it is considered that the birth of psychometry dates back to the mid-nineteenth century, when Francis Galton began to work on establishing mechanisms to measure the existence of individual differences between individuals.

Galton would use mechanisms centered on the measurement of physiological elements, his studies being limited to basic processes. But thanks to his studies, fundamental concepts in psychometry emerged, such as the principles of correlation between variables and regression, which would be formalized over time.which would eventually be formalized by Karl Pearson, his student.

The first psychological tests

Cattell first devised the concept of mental testing, applying it to the measurement of sensory abilities, but it was not until Alfred Binet that scales for measuring intellectual abilities began to be developed. Binet, together with his assistant Theodore Simon, created the first intelligence scale based on functional criteria..

Later, over time, various types of scales were developed, some of which were even used in the army (such as the Army Alpha and Army Beta, used to classify soldiers according to their level of intelligence). Subsequently, they would also the presence of possible cultural biases would also be taken into account for a correct analysis of the for a correct analysis of mental capacity.

Spearman would interpret Pearson's correlation as followsindicating that the presence of a correlation between variables evidences the presence of a common element. On this basis he would eventually generate his theory of the G-factor of intelligence.

Later developments

Some of the main authors that allowed the development of psychometrics were mainly the aforementioned Galton, Binet, Pearson and Spearman, although many other authors would have a key role in this discipline.

Spearman would elaborate the classical theory of tests according to which the scores obtained in the tests should be compared with the group of the test takers. should be compared with the reference group in order to be able to in order to give them meaning, although this limits their reliability and validity as the results can change depending on who the comparison is made with.

Over time, other theories would emerge, such as the item response theorywhich would try to combat this limitation by proposing the test as a way of measuring the level of a subject in a given trait, interpreted on the basis of statistical probability. Over time, other tests such as aptitude or personality tests would emerge.

Some applications and usefulness of psychometrics

Psychometry is a discipline of special importance for psychology, since it allows to operationalize the different mental processes and make measurements, set criteria, establish comparisons and even develop explanatory and predictive models. In addition, it makes it possible to relate variables and help to establish the existence of relationships between them.

All this is necessary in many different areassuch as, for example, in the following.

Clinical psychology

The different tests and measures of psychological evaluation are of great importance in clinical practice. Being able to make measurements with respect to characteristics or mental states allows us to visualize and to get an idea of the patient's condition and severity, as well as to prioritize certainand prioritize certain aspects during the treatment according to the patient's characteristics.

Neuropsychology

Psychological and neuropsychological tests and evaluations give us clues as to how the patient is doing. give us clues as to how a subject's mental capacities are in comparison with an established criterion, the population average or his or her own state in previous measurements.

3. Developmental assessment

Throughout our life cycle we develop our capacities in a certain way. The presence of alterations in this development can be detected thanks to various procedures developed through psychometrics, allowing dysfunctional elements that hinder the adaptation of the person to the environment to be foreseen and treated.

4. Evaluation of capacities

Personality characteristics, abilities and skills are some of the many elements whose measurability has emerged from instruments developed through psychometrics.

5. Human resources

Determining an individual's ability to cope with a given job is not a simple task. Hiring or not hiring an individual must take into account his or her level of ability and mental state in order to detect the level of suitability for the position and the company.

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

6. Research

Psychology is a science that is continually advancing. Research is an essential element in order to achieve a better understanding of the psyche and reality. Establishing relationships between different situations and/or stimuli and/or generating data that can be contrasted are key aspects in this process, for which psychometry is essential as it is the basis for the creation of measurement methods.

On the other hand, psychometry implies a discussion on the extent to which the way of operationalizing hypotheses in measurement tools and concrete variables is reasonable or not, and what are the epistemological limits of doing so.

Methodological problems

Psychometrics does not provide us with tools that allow us to capture a totally objective picture of the psychological predispositions of the subjects studied. There are many limitations linked to psychometric methods and tools.

For example, a frequent problem is the fact that the context in which psychological tests are passed affect the way in which the subjects studied behave.. Something as simple as dislike or antipathy towards the person passing an assessment tool can bias the results obtained, as can nerves when faced with the need to do something to which one is not accustomed (filling out several sheets of paper with tests that measure intelligence, for example).

On the other hand, those personality tests that are based on self-reporting do not exactly measure do not exactly measure behavioral patterns that characterize those personality patterns, but rather the way in which individuals see themselves. That is, between what one wants to study and the data obtained there is a filter of introspection: one must stop to think about one's actions, and offer an interpretation of them. Esto no es ideal, aunque si asumimos que la mayoría de los sujetos estudiados tienden a responder de manera honesta, puede ayudar a acercarse a su personalidad, sus hábitos, etc.

Referencias bibliográficas:

• Borsboom, D. (2005). Measuring the Mind: Conceptual Issues in Contemporary Psychometrics. Cambridge: Cambridge University Press.
• Beriot, D. y Exiga, A. (1970). Les tests en procès: les abus de la psychotechnique, Paris, Dunod Actualité.
• Embretson, S.E., y Reise, S.P. (2000). Item Response Theory for Psychologists. Mahwah, NJ: Erlbaum.
• Humphreys, L.G. (1987). Psychometrics considerations in the evaluation of intraspecies differences in intelligence. Behav Brain Sci. 10 (4): 668–669.
• Kaplan, R.M., y Saccuzzo, D.P. (2010). Psychological Testing: Principles, Applications, and Issues. (8va edición). Belmont, CA: Wadsworth, Cengage Learning.
• Michell, J. (1997). Quantitative science and the definition of measurement in psychology. British Journal of Psychology. 88 (3): 355–383.