An excellent example of quota sampling involves a market research company aiming to survey consumer preferences for a new beverage product, ensuring specific demographic groups are proportionally represented in their sample.
Understanding Quota Sampling
Quota sampling is a non-probability sampling method where the researcher defines specific quotas for different subgroups within a population based on predetermined criteria. These criteria might include characteristics such as age, gender, occupation, or socioeconomic status. The goal is to ensure that the final sample reflects the proportions of these subgroups in the overall population, even though the selection of individual participants within those subgroups is non-random. Researchers actively seek participants until these precise proportions are met for each category.
Practical Example: Market Research Survey
Consider a scenario where a company wants to understand consumer opinions on a new energy drink. They decide to use quota sampling to ensure their survey participants accurately represent the target market's demographics.
Defining Quotas
The researchers determine that their sample of 300 participants should reflect the following demographic breakdown, based on known population statistics or marketing targets:
| Demographic Category | Quota Percentage | Target Number of Participants |
|---|---|---|
| Gender | ||
| Male | 55% | 165 |
| Female | 45% | 135 |
| Age Group | ||
| 18-24 years | 30% | 90 |
| 25-34 years | 40% | 120 |
| 35-50 years | 20% | 60 |
| 50+ years | 10% | 30 |
Execution of the Sample
Field interviewers are deployed to various public locations, such as shopping malls, parks, or city centers, with instructions to recruit participants until each quota is filled.
- Targeted Recruitment: An interviewer might approach individuals and first determine their gender and age group. If they have already met their quota for, say, "males aged 25-34," they will then only seek participants from other under-represented categories.
- Stopping Criteria: Once the required number of participants for a particular demographic segment (e.g., 165 males or 90 individuals aged 18-24) has been interviewed, the recruitment for that specific quota ceases.
- Ensuring Representation: The process continues until all target numbers across all demographic categories are reached, ensuring that the final sample of 300 participants precisely matches the predefined proportions for gender and age.
This method allows the researchers to quickly gather data while maintaining control over the demographic composition of their sample, making it a cost-effective and efficient approach for specific research objectives where representativeness of key characteristics is crucial.
