These are different ways of assessing the quality of measurement instruments used in science.
We can weigh ourselves on a scale, or measure our height with a meter, or assess body temperature with a thermometer. The data that we obtain in principle should be objective and reliable, in addition to referring specifically to what we wanted to measure (weight, height or temperature). But, what if in addition to that they also reflected other things such as volume or color or were influenced by atmospheric pressure or humidity? Our results would not be totally valid, since we would not be looking only at the characteristics that we wanted to assess.
In psychology, a science whose object of study is not directly observable and in which different constructs are analyzed, validity is something that must be carefully considered in order to guarantee that we are evaluating what we must evaluate. It is something essential, for example, to evaluate the mental state of a subject or assess the effectiveness of a treatment. And it must be taken into account that, depending on what is being analyzed, we can find different types of validity. In this article we are going to review what they are.
What is validity?
Before seeing what the different types of validity are, it is advisable to do a little review about what this term refers to.
Validity is understood to be the property or capacity of a test or other measuring instrument to adequately measure what said instrument has been generated for, regardless of the theory or model of reality from which it was developed. It is linked to what is measured and how it is measured, assessing whether the measurement is carried out correctly. That is: that the measurement data corresponds to the actual data.
Validity can be calculated based on the validity coefficient, based on the degree of correlation between the measured variable and the one studied.
The different types of validity
Validity is a fundamental property when making measurements of any kind. As we have commented in the introduction, in sciences such as psychology it is essential to take this aspect into account in order to generate valid measurement instruments to evaluate the state of the people analyzed. But validity can be considered from different perspectives, being able to find different types of validity focused on different aspects.
1. Construct validity
This type of validity refers to the accuracy with which the measuring instrument measures what it is originally intended to measure. In other words, it assesses the extent to which the responses or results of the evaluation method used have a specific meaning, with a relationship between what is observed and the construct of interest.
2. Content validity
It is the degree to which a measurement instrument contains representative items of the construct or content that is intended to be evaluated. It is valued that aspects of interest that represent the attribute to be evaluated are included in the elements that are part of the measurement. Within it, two major types of validity can be assessed.
3. Apparent validity
Although it is not truly a type of validity, it refers to the degree to which a test appears to assess a certain attribute. In other words, it is the appearance of validity that an instrument can give to whoever looks at it, without any kind of analysis. It has no real significance.
4. Logical validity
This is the type of validity used to generate an instrument and measurement items, depending on the representativeness of what is analyzed in the valued content.
5. Validity of criteria
It refers to the degree to which a test correlates with scales and external variables, being able to relate the results of the measurement to a specific criterion. It also allows to establish predictions.
6. Predictive validity
Type of criterion validity that allows to establish predictions regarding behavior, from the comparison between the values of the instrument and the criterion. Generally, a time elapses between the moment of measurement and that of the criterion used.
7. Concurrent validity
Both the measurement and the verification of the criterion are carried out at the same time, allowing to relate both elements and assess the current state of the subject.
8. Retrospective validity
Unusual type of validity in which the item or evaluation method assesses the existence of a certain value or trait in the past. The criterion is taken before the measurement of the test.
9. Convergent validity
This type of validity refers to the validity obtained from the relationship of two measuring instruments. Convergent validity indicates the existence of a relationship between two tests that evaluate the same thing, that is, it indicates the existence of an interrelation or correspondence between both measurement instruments.
10. Discriminant or divergent validity
Divergent validity is the other side of the coin of convergent validity. In this case, we are talking about the degree to which two tests or instruments differ, reflecting that two tests that are associated with different constructs or elements. That is, it is reflected that two instruments referring to two constructs that should be different have different results.
- Antequera, J. and Hernángomez, L. (2012). Experimental psychology. CEDE Preparation Manual PIR, 09. CEDE: Madrid
- Prieto, G .; Delgado, AR (2010). Reliability and validity. Psychologist Papers, 31 (1): 67-74.