The 10 Fundamental Types of Validity 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, as well as 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 fully valid, since we would not be looking at only the characteristics that we wanted to assess.

In psychology, a science whose object of study is not directly observable and in which different constructs, validity is something that must be carefully considered to ensure that we are evaluating what we must evaluate. It is essential, for example, to assess 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 analysed, we can find different types of validity. In this article we are going to review what they are.

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What is validity?

Before seeing what the different types of validity are, it is advisable to do a brief review of what this term refers to.

Validity is understood as the property or ability of a test or other measurement instrument to adequately measure what the instrument has been created 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 done, assessing whether the measurement is carried out correctly. This is: that the measurement data corresponds to the real data.

The validity can be calculated based on the validity coefficient, based on the degree of correlation between the measured variable and the one studied.

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The different types of validity

Validity is a fundamental property when making measurements of any kind. As we have mentioned 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 assess 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 measurement instrument measures what in principle it is intended to measure. In other words, it assesses to what extent the answers or results of the evaluation method used have a concrete meaning, there is a relationship between what is observed and the construct of interest.

2. content validity

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. face validity

Although it is not truly a type of validity, it refers to the degree to which a test appears to value a certain attribute. In other words, it is the appearance of validity that an instrument can give to whoever looks at it, without any type of analysis. It has no real meaning.

4. logical validity

This is the type of validity used to generate an instrument and measurement items, based on the representativeness of what was analyzed in the valued content.

5. Criterion validity

It refers to degree to which a test correlates with scales and external variables, being able to relate the results of the measurement with a specific criterion. It also allows making predictions.

6. predictive validity

Type of criterion validity that allows make predictions about behavior, from the comparison between the values ​​of the instrument and the criterion. Generally, a period of time elapses between the moment of measurement and the moment of the criterion used.

7. concurrent validity

Both the measurement and the verification of the criteria are carried out at the same time, allowing to relate both elements and assess the current state of the subject.

8. retrospective validity

An 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 measurement 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 measuring instruments.

10. Discriminant or divergent validity

Divergent validity is the other side of the convergent validity coin. In this case, we are talking about the degree to which two tests or instruments differ, reflecting that two tests are associated with different constructs or elements. That is, it reflects that two instruments referring to two constructs that should be different have different results.

Bibliographic references

• Antequera, J. and Hernangomez, L. (2012). Experimental psychology. CEDE PIR Preparation Manual, 09. CEDE: Madrid
• Prieto, G.; Delgado, A.R. (2010). Reliability and validity. Psychologist Papers, 31 (1): 67-74.