QUALITATIVE VARIABLE: EXAMPLES, TYPES, CHARACTERISTICS - SCIENCE - 2025

A qualitative variable, also called a categorical variable, is one that takes a characteristic into consideration. Its function is the expression of qualities or peculiarities of people, objects or situations that are not numerical in nature.

In general, they are non-numeric variables. For example, hair color, nationality, cat breeds, city of residence, clothing brand, university, colors, names, religion, political parties, professions…

Colors can be used as qualitative variables. Source: pixabay.com

Take the example of an investigation; We want to investigate how the city in which one lives (qualitative independent variable) influences the religion one professes (qualitative dependent variable).

This type of variable allows those elements that are not numerical to be expressed in the statistical scope. As these are qualities and not numbers, the results of research that include qualitative variables tend to be general and not specific.

Despite not being numerical, qualitative variables can also be used in purely financial or economic areas; in those cases each category assumes a number that identifies it.

characteristics

- Qualitative variables are characterized by not being numerical. Rather, they consider qualities and characteristics that are relevant in a specific context.

- The qualities considered as qualitative variables have a place within a particular category. For example, they can be colors, names of people, cities, countries, among others.

- They are finite. This characteristic is common for all types of variables, since a certain number of values ​​are always considered that are relevant in relation to the particular topic to be investigated.

- Since they encompass qualities and characteristics, qualitative variables are divided into various types according to the nature of that specific quality. They can be nominal, ordinal, or binary.

- Sometimes qualitative variables can be assigned numbers. This is intended to allow for a more reliable statistical analysis.

Types

Qualitative variables can be divided according to several criteria. We will describe the main categories below:

- According to the amount of values ​​considered

Dichotomous

Dichotomous qualitative variables can only consider two values. Examples are sex (male or female), or affirmation or negation.

Politics

These variables are characterized because they contemplate three or more values. Within these you can find scales that imply a certain order (such as: good, regular, bad) or scales that do not have an associated order (for example, colors).

- According to the nature of the variable

Binary

Qualitative binary variables consider two values, which are assigned numbers (0 or 1). This type of variable is widely used in the economic, financial, statistical and biological fields.

The values ​​taken into account as qualitative binary variables must be exhaustive. In other words, the options chosen must cover all the possibilities that may be generated related to said values.

Likewise, the values ​​must be mutually exclusive; that is, one option must override the other, the fact that a certain value is given makes it impossible to give another.

Thanks to these types of variables, it is possible to perform statistical analysis of more complex scenarios without having advanced mathematical knowledge. They are very useful when solving problems in which the main factors to consider are not numerical values, but other types of qualities.

Nominal

This type of qualitative variables does not respond to any specific order. The values ​​that make up this category are not governed by ordinal scales; rather they correspond to characteristics with a high degree of independence in relation to each other.

Nominal variables are considered to have lower mathematical precision; for this reason, they are less used in these areas.

Ordinal

Ordinal variables are those that do imply a scale of order; that is, they are subject to ordinal criteria. They are also known as quasi-quantitative variables.

The values ​​that make up this category must conform to some specific classification. Likewise, the intervals that exist between one value and another may not be uniform, but there must always be an order relationship.

Examples of qualitative variables

- The fear

This is a nominal qualitative variable, since it cannot be measured numerically. Fear is a variable that changes according to the person who feels it and fluctuates depending on the situation in which they feel when reacting to a certain event or event.

- Hunger

Hunger cannot be measured numerically, therefore, it is considered as an ordinal qualitative variable. This variable can only be perceived by the person who feels it and can be classified as a lot, a little or nothing, depending on the specific situation or time.

- The beauty

This variable is a concept that can only be measured by the individual who interprets it. Beauty is a quality that has no numerical value and cannot be classified within a ranking. Therefore, it is a nominal qualitative variable.

- Civil status

A person's marital status is a nominal qualitative variable to which a numerical value cannot be assigned. It is a concept that does not have a specific order established.

- The happiness

This variable cannot be measured numerically because it depends on the value that each person assigns to it. Happiness is a property that each individual feels subjectively and there is no tool to measure the degree of happiness that a person can feel.

- The ignorance

This variable cannot be measured numerically and is expressed in attitudes and specific moments.

- Utility

The variable that determines how useful an object is is clearly qualitative. In this way, the utility is perceived by each individual according to a specific situation.

- The type of medal

This is an ordinal qualitative variable, since there is a classification by categories that assigns a place within a competition. In this way, the gold, silver and bronze medals denote the place occupied in a competition without the need to assign a numerical value to the results.

- The creativity

This variable is qualitative since creativity cannot be measured numerically. In the same way, it is a factor that varies from person to person depending on the specific moment in which it takes place.

- The grade of an exam

When an exam is graded with the terms passed, excellent, acceptable or poor, it is an ordinal qualitative variable, since a numerical value is not being assigned to the result, but it is being given a place within a scale of value.

Examples of binary variables

- A study related to the number of people who have died of pancreatic cancer in a given hospital during a specific period of time. In this case, variables 1 and 0 can be applied to the values ​​"died from pancreatic cancer" and "died from conditions other than pancreatic cancer", respectively.

- Population censuses in which we want to determine how many men and how many women live in a given geographical space. In this case the value "1" can be related to men and the value "0" to women.

- A survey through which you want to know how many university students in a given sector agree with the educational measures proposed by the government entity. The value "1" can be associated with the affirmative answer and the value "2" can be associated with the negative answer.

Examples of nominal variables

- A survey in a specific community that seeks to know the opinion of the neighbors in relation to the preferred colors to paint the facade of the building where they live. In this case the options can be white, beige, light blue or light green.

- A survey carried out in a specific municipality whose intention is to find out the number of foreigners who live in said space considering a specific period. Nominal variables can be Colombian, Peruvian, Venezuelan or Ecuadorian nationalities.

- A sociological study that delves into the main communication channels through which the inhabitants of a specific sector obtain the news information they consume. The variables considered can be television newscasts, radio newscasts, Facebook or Twitter.

Examples of ordinal variables

- A study carried out by a clothing store that seeks to measure the level of customer satisfaction. The variables considered in this case can be "very satisfied", "moderately satisfied" and "dissatisfied".

- Surveys carried out by the governmental bodies of a specific country to determine the educational conditions of its inhabitants. The variables to take into account can be "low educational level", "medium educational level" and "high educational level".

- A survey carried out in a classroom after having given tools related to a specific topic, with the intention of verifying if the contents taught have been well understood by the students. According to the students' responses, the following ordinal variables can be used: "very good", "good", "fair", "bad" and "very bad".

References

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