Psychometrics: what is it and what is it responsible for?

Psychology is the science that studies the mind and mental processes. However, these processes are not directly observable by humans, nor are they easily quantifiable. We can observe that a person acts in an extroverted way, but it is not easy to determine to what degree 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 is the object of study of psychometry. Next we will talk about this area of ​​psychology.

• Related article: "The 12 branches (or fields) of Psychology”

Psychometry as a measurement of the psyche

Psychometry is understood as the discipline that 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 comparison and contrast with other people or with specific criteria that can be used to establish and test theories and hypotheses about the operation of the mind. Thanks to psychometry

it is possible to quantify and operationalize the psychic, having largely allowed the development of psychology as a science.

As the mind is something 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 activity registration physiological.

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

• You may be interested: "Types of intelligence tests"

Which comprises?

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, establishing a theory that can link mental characteristics with measurable elements, on the other the creation of measurement scales, and finally involves the development of mechanisms and instruments that allow such measurement.

1. The creation of the theory

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

2. The scales

The creation of scales or escalation is another of the basic elements of which psychometry is responsible. These scales allow assigning specific values ​​to the variables analyzed, so that they can be operationalized and work with them. It is about 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 them are psychological tests. In this elaboration we must bear in mind that it is necessary to seek objectivity, consistency, the ability to discriminate between subjects, and that they be valid and reliable.

Some relevant concepts

As a discipline that allows the measurement of the unobservable from the observable, psychometry has to take into account various concepts in order for said measurement to be correct and representative. Some of the most relevant concepts are the following.

1. Correlation

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

2. Variance and standard deviation

The variance is the degree to which the scores of a test or of the same variable they can disperse. The standard deviation refers to how much the scores are usually expected to disperse relative 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 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 elements that we are using to measure you are measuring what you want to measure. There are various types of validity, such as construct, content or ecological validity.

A little history

The history of psychology is closely linked to that of measuring the 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, which would begin to conduct experiments in which he tried to measure reaction times and he 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 middle of the 19th century, when Francis Galton he would begin to 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 thanks to his studies, fundamental concepts emerged in psychometry, as the principles of correlation between variables and regression, which would eventually be formalized by Karl Pearson, his student.

The first psychological tests

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

Subsequently, over time, various types of scales would be made, some even used in the Army (such as Army Alpha and Army Beta, used to classify soldiers according to their level of intelligence). Later also an attempt would be made to take into account the presence of possible cultural biases facing a correct analysis of mental capacity.

Spearman would interpret Pearson's correlation, indicating that the presence of a correlation between variables shows the presence of a common element. Based on this, he would end up generating his theory about the intelligence G factor.

Later developments

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

Spearman would develop the classical theory of tests according to which the scores obtained in the tests should be compared with the reference group in order to give them meaning, although this limits their reliability and validity by being able to change the results according to whom the comparison is made with.

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

• Related article: "Types of psychological tests: their functions and characteristics”

Some applications and usefulness of psychometry

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

All this is necessary in very different areas, as for example in the following.

1. Clinical psychology

The different tests and psychological evaluation measures are of great importance in clinical practice. Being able to make measurements regarding characteristics or mental states allows us to visualize and get an idea of ​​the state and gravity of the subject, as well as prioritizing certain aspects during treatment according to the characteristics of the patient.

• You may be interested: "Clinical psychology: definition and functions of the clinical psychologist”

2. Neuropsychology

Psychological and neuropsychological tests and evaluations they give us clues as to how the mental capacities of a subject are compared to an established criterion, the population mean or his own state in previous measurements.

3. Development evaluation

Throughout our life cycle we develop our capacities in a certain way. The presence of alterations in said development can be detected thanks to various procedures elaborated thanks to psychometry, allowing that dysfunctional elements that make it difficult for the person to adapt to the environment are anticipated and treated.

4. Capability assessment

Personality characteristics, abilities and skills are some of the multiple elements whose measurement possibility has emerged from instruments developed thanks to psychometry.

5. Human Resources

Determining the ability of an individual to cope with a certain job is not an easy task. Hiring or not hiring an individual You must take into account your level of ability and your state of mind 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 his level of ability in different aspects.

6. Investigation

Psychology is a continually advancing science. Research is an essential element in order to get 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 methods of measurement.

On the other hand, psychometrics implies the discussion about to what extent the way to operationalize the hypotheses in measurement tools and specific variables is reasonable or not, and what are the epistemological limits of doing it that way? way.

Methodological problems

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

For example, a common 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 dislike for someone who passes an evaluation tool can skew the results obtained, just like the results obtained. nerves at the need to do something to which they are not accustomed (fill out several pages with tests that measure intelligence, for example).

On the other hand, those personality tests that are based on self-report They do not exactly measure patterns of behavior that characterize those personality patterns, but the way in which individuals see themselves. That is, between what you want to study and the data obtained there is an introspection filter: one must stop to think about their actions, and offer an interpretation about them. This is not ideal, although if we assume that most of the subjects studied tend to answer honestly, it can help to get closer to their personality, their habits, etc.

Bibliographic references:

• Borsboom, D. (2005). Measuring the Mind: Conceptual Issues in Contemporary Psychometrics. Cambridge: Cambridge University Press.
• Beriot, D. and Exiga, A. (1970). Les tests en procès: les abuses de la psychotechnique, Paris, Dunod Actualité.
• Embretson, S.E., and 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., and Saccuzzo, D.P. (2010). Psychological Testing: Principles, Applications, and Issues. (8th edition). 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.