15 examples of qualitative variables, with explanations

Several examples of qualitative variables widely used in social science research.

Throughout this article we are going to see some examples of qualitative variables very studied in science, in order to make easier the understanding of the concept.

What are qualitative variables?

Research helps professionals in different disciplines to improve their understanding of the dimensions of reality with which they deal. Thanks to research it is possible to assess that a drug or treatment is or is not effective, or that it is more effective than another, and it even makes it possible to create technologies and scientific advances of great relevance.

But to investigate it is necessary to take into account that there are many elements that affect what we want to analyze. There are innumerable variables to take into account. And the study of these and their interaction is fundamental for the scientific explanation of reality.

Among the different variables, we can find two large groups depending on the way we can deal with them. Some of them allow us to measure aspects of reality and observe mathematical relationships between their values: quantitative variables. Others allow us to see that there is a quality or not that we are observing, but do not allow its measurement (especially when we are talking about abstract elements): these are qualitative variables.

Characteristics of this scientific concept

A qualitative variable is understood to be any type of characteristic or category that serves to classify a parcel of reality into several non-numerical values which make it possible to assess the presence of differences or fluctuations with respect to this characteristic among the different subjects to be analyzed.

A qualitative variable is one that focuses on the quality, condition or characteristic and classifies reality on the basis of categories that cannot be quantified numerically (as opposed to quantitative variables, which make it possible to assess the quantities of these variables).

In other words, qualitative variables are those whose values are not measurable with measuring instruments and which do not present a measurable quantity by themselves. do not have a measurable quantity in themselves.. Thus, wherever we find examples of qualitative variables, we will mainly find indications as to whether or not the subjects studied have a quality that cannot be accumulated from less to more quantity by using values with the same numerical distance from each other.

These variables can be either nominal (they only serve to differentiate subjects into different categories) or ordinal (in addition to the above, they allow establishing an order, although they do not allow observing mathematical relationships between their values). They can also be dichotomous (when there are only two possible values) or polynomial (when the variable can have more than two possible values).

15 examples of qualitative variables

Below you will find a series of examples of typical qualitative variables, although it should be noted that it is often possible to make a variable of this type operationalizable and quantitative.

1. Gender

Probably the most common qualitative variable in scientific research, at least when analyzing aspects related to human behavior and health. This variable has two values in its more traditional conception, or three if we take into account the existence of intersex persons. It is necessary to bear in mind that we are talking about sex at the biological level, not about sexual or gender identity..

Thus, we could find the values man, woman and intersex, which establish a categorization of the subjects in such a way that the category itself only establishes that the subject is part of one or another group, being a nominal qualitative: being one thing or another does not allow to establish a hierarchy or order or to perform mathematical operations or transformations with its values.

2. Gender/sexual identity

In addition to biological sex, sexual or gender identity is also a nominal qualitative variable. Individuals can be cisgender or transgender, for example, expressing this category only a characteristic of your person which is not directly quantifiable..

3. Sexual orientation

Another nominal qualitative variable can be sexual orientation: the category in question establishes a distinctive element without any kind of order or numerical relationship. Heterosexual, homosexual, bisexual, asexual, pansexual? there is a large number of possible categories.

4. Marital status

Like sex, marital status is another qualitative variable of a nominal type, whose values establish a quality or property in which different people can be differentiated but without any numerical relationship between their values. It only establishes whether or not the subject has a partner.. Single, married/partnered or widowed are some of the most common and well-known values, in addition to separated or divorced.

5. Ethnicity/Race

Another example of a qualitative variable that appears more in the social sciences is that of ethnicity or race, in this case it is also a nominal variable.. For example, being Caucasian or African-American (among others) allows us to distinguish different ethnicities, but without there being an order or numerical relationship between these factors.

6. Religious confession

The religious confession of a person can be considered a type of qualitative variable: it only establishes a quality of a person.

Being an atheist, agnostic, Christian, Muslim, Jew, Hindu, Buddhist, or a member of another religious denomination can be considered a qualitative variable.Buddhist or member of another of the multiple existing religious confessions is something that can differentiate the beliefs and the way of being of people, but without there being any type of ordering or numerical relationship between them.

7. Profession

Our profession or trade is also a nominal qualitative variable. Being a psychologist, doctor, architect, bricklayer, plumber or priest simply allows us to be allows us to categorize ourselves within a group, but it does not allow us tobut it does not allow us to order people or to establish numerical relationships between the different professions.

8. Schooling

This time we are dealing with an ordinal type of qualitative variable: There is a progression between the different levels and it allows comparisons to be made by using ordered categories, although they do not have numerical values per se.even though they do not have numerical values per se.

Thus, we can see people with no studies, with primary studies, secondary studies and higher studies. One has no more value than the other, but someone with secondary education must have done primary education before, for example.

9. Socioeconomic level

Like schooling, this is an ordinal qualitative variable: having a high socioeconomic level implies a higher degree of this variable than someone with a low level, although a numerical relationship cannot be established.

10. Position

Although we have mentioned that the profession is a nominal qualitative variable, the position we occupy within this variable is a qualitative variable of the ordinal type, the position we occupy within that profession can be considered ordinal (although it is still qualitative). (although it is still qualitative): a hierarchical order can be established between the different positions, for example from private to general or from cook to chef.

11. Color

Green, blue, red, white... The color is another example of a nominal qualitative variableThe color is another example of a nominal qualitative variable, since it only indicates a quality of the object that differentiates it from others. We cannot establish any kind of numerical relationship between its values. However, it must be taken into account that this variable could become quantitative if instead of color we measure wavelength (in which there are numerical values that can be operationalized).

12. Blood group

Another nominal qualitative variable can be the blood group. Having blood group A, B, AB or O in its positive or negative levels does not allow us to make an ordering or to establish numerical relationships (for example, someone who has A+ blood does not have twice as much as B+ blood).

13. Brand

The brand of the products we use is another possible qualitative variable of a nominal type, which can be used, for example, in studies on the can be used, for example, in market research..

The brand itself can only provide us with information on whether or not this value of the variable is present. However, it should be borne in mind that if we go on to analyze the number or frequency of use of this brand, we will already be using a quantitative variable.

14. State of mind

By itself, mood (from which we could extract different variables such as happiness, sadness, etc.) is a qualitative variable.

Another thing is that by means of specialized instruments a representative measurement of mood can be made by operationalizing this phenomenon (for example, we can use tests such as the BDI to measure levels of depression); but by itself, being sad, happy or euthymic is a qualitative variable. the fact of being sad, happy or euthymic provides values of a variable that does not allow us to establish numerical relationships between them.

15. First name (and last name)

We probably do not usually think of them as a variable, but the truth is that our first and last names can be considered and treated as nominal qualitative variables.

Jaime is not Pablo, but it is not possible to establish an order or visualize any numerical relationship with these values (since if, for example, we were to count the number of Jaimes and Pablos, the variable would become Number of Jaimes/Pablos and this would already be quantitative).

The same happens with the surnames. They serve to group the members of the same family, but they do not serve to order them, nor can we establish numerical relationships with them. nor can we establish numerical relationships with this variable per se.