Quota sampling: Types, examples, steps

Quota Sampling Definition

Quota sampling is a non-probabilistic technique where the researcher creates a convenience sample in which the individuals are representatives of the population. These individuals are chosen on the basis of specified qualities. These quotas are created so that they become useful in data collection. Furthermore, these samples represent the entire population. Lastly, the final subset is decided as per the knowledge of the researcher regarding the population.

An Example of Quota Sampling

A cigarette company desires to investigate what age group desires what cigarette brand in a specific city. For this purpose, the company will apply a survey quota to the age groups of 21–30, 31–40, 41–50, and 51+. Then the company will collect the information from different age groups. Lastly, from the provided information, the company will estimate the smoking trend in that city.

Types of quota sampling

There are two types of quota sampling: controlled quota sampling and uncontrolled quota sampling. Both of them are explained one by one.

Controlled quota sampling:

In this type of quota sampling method, there is a restriction on the researcher in selecting the sample. The researcher has a limited selection of samples.

Uncontrolled quota sampling:

In this type of quota sampling method, there is no restriction on the researcher regarding the choice of the samples.

Quota sampling examples

Many examples of the quota sampling method can be presented.

Quota sampling example 1:

A researcher is interested in knowing the smartphone brand preference in ten cities in a country. For this purpose, he or she decides to select 500 participants. The researcher can divide the population in the following quotas:

Gender: male respondents = 250, female respondents= 250

Age: From the respondents, the researcher selects 100 respondents each between ages of

16-20=100 respondents

21–30 = 100 respondents

31–40 = 100 respondents

41-50=100 respondents

51+=100 respondents

Total: 500 respondents

Employment status: 300 employed, 200 unemployed

Location: 50 respondents per city

Here, the researcher can apply quotas based on the sampling frame. Furthermore, equal division of quotas is not necessary. Consequently, the quotas can be divided on the basis of the needs of the researcher. Lastly, to reach the respondents, random sampling can be conducted.

Quota sampling example 2:

Suppose you promote an industry event on your page. There is an opportunity for you to serve the signed-up people with awesome follow-up content. For example, you can ask them to choose the answer that describes their role. On the basis of their job role, you can prepare content that can be helpful for them. After that, the quota sampling process can be used to enlist the people on the basis of their responses. Lastly, you can share the content and identify the opens, clicks, and rates of their responses.

Quota sampling example 3:

A researcher can discover how supply chain sustainability and transparency influence customer purchasing decisions for clothing, accessories, and shoes. For that purpose, the researcher needs to apply quotas to the age group between 17 and 75 in the biggest markets.

Steps to perform the quota sampling technique:

Since the quota sampling technique is a non-probability sampling technique, the rules for forming the sample are not available. But usually, four steps are used for the formation of quota sampling.

1. The sample population is divided into subgroups:

The whole population is divided into mutually exhaustive groups with the help of stratified random sampling. For this, the researcher uses random selection.

2. The weightage of subgroups is figured out:

The researcher then estimates the proportion in which there are subgroups in the population. This sampling method is used to maintain this proportion in the sample. For instance, if 60% of the purchasers between the ages of 30 and 40 are interested in purchasing a product, then the sample that the researcher will select will have 60% of the purchasers between the ages of 30 and 40.

3. Selection of a suitable size for the sample:

This step allows researcher to select the size of sample keeping in mind the proportion. For example, if the population size is five hundred, he or she can select the sample of 50 from that population.

4. The defined quotas are used to conduct surveys:

In this step, the researcher uses each quota to complete the surveys. It has to be made sure that the researcher remains stick to the predefined quotas for the achievement of actual practical results.

Characteristics of quota sampling:

The following are the characteristics of quota sampling.

1. The population is divided into subgroups.
2. The focus of quota sampling is to represent the best respondents in the final sample.
3. Estimations produced are represented in a better way.
4. The samples are of various qualities.
5. Due to quota sampling, there is economy of time with regard to data collection.
6. If the population is represented accurately in the quotas, then costs are saved.
7. The entire population is covered in the quota sampling.
8. In this sampling, the specific group of people is identified.

Advantages of quota sampling:

Advantages of quota sampling are discussed in the following paragraphs.

1. The process of sampling is quick, therefore, it saves time.
2. The research process in quota sampling becomes convenient as interpretation of information, and responses to the survey are simple.
3. Due to use of this sampling technique, there are no chances of over-representation of population.
4. This sampling technique helps in saving the money.

Disadvantages of quota sampling:

Some of the limitations of quota sampling are discussed here.

1. Since this method follows the non- random sampling technique, there are chances of biasedness. Resultantly, the data may become less reliable.
2. The researchers cannot calculate the sampling error. It is because this technique is non-probability sampling method.
3. The results obtained from quota sampling cannot be generalized about the wider population.

Applications of quota sampling:

Some of the situations in which this sampling technique is used are described below.

1. When the researcher faces time constraints, he or she used quota sampling technique. Thus the idea about the entire population of interest can be obtained in a short period of time.
2. It helps the researcher in filtering the characteristics in formation of subgroups. Hence the researcher can easily obtain the desired results.
3. The quota sampling is used when the researcher faces financial constraints. In this situation the researcher uses quotas for getting the picture of the whole population.
4. Quota sampling is beneficial when the researcher gets the respondents to him or her randomly such surveys on websites, or street surveys.
5. If the researcher is desirous to get quick results, then he or she relies on quota sampling.
6. This sampling technique is also used in situations in which the researcher wants to find out the relationship between the groups.

Quota sampling and stratified random sampling:

In both quota sampling and stratified sampling, the population is divided in distinct subgroups and predetermined individuals from each subgroup.

The difference between the two is that quota sampling is a non-probability sampling method whereas the stratified sampling is a probability sampling method.

In stratified random sampling technique, the sample is randomly selected. On the other hand, in quota sampling, the researchers select the sample as opposed to randomly selecting it.