Purposive Sampling, PDF

What Is Purposive Sampling?

Purposive sampling is one of the non-probability sampling methods in which researchers select specific units because they have the characteristics necessary in their samples for their research work.  Also referred to as deliberate,  judgmental, or subjective sampling, it is a sampling technique that depends on the judgment of the researchers when they identify and choose the cases, events, or individuals that can bring out the best information to full the key objectives of the study. 

Based on a research report published by Knowledge Sourcing Intelligence, a compound annual growth rate of more than 16% through 2026 is anticipated in the global online survey market. That’s why many market researchers and analysts in business firms and organizations use online surveys and survey reports while using various sampling techniques like purposive sampling, stratified sampling, convenience sampling, and many others to collect clear insights into the market, and forecast processes, and to facilitate working on loopholes for increased efficiency levels. 

Types of Purposive Sampling

Purposive sampling is classified into different types of sampling methods that you can use to create a purposive sample for your research work plan. These are critical case sampling, expert sampling, extreme case sampling, heterogeneous case sampling, homogenous case sampling, typical case sampling, and total population sampling. Think carefully about the main purpose of your research study to identify which type of purposive sampling is suitable for you.

Critical Case Sampling: One of the widely-used types of purposive sampling methods is critical case sampling. Researchers use this research methodology when they select one case for investigation so that additional data and in-depth insights into other similar cases will be shown. Expert Sampling: Do you need to obtain information that is rooted in a certain type of expertise? Expert sampling is a type of purposive sampling method that enables you to engage niche groups and other researchers who are trying to acquire an initial understanding of a topic. Extreme or Deviant Case Sampling: This case sampling allows the researchers to investigate the outliers or observations that deviate significantly from other observations in the sample when it comes to a certain trend. Analyze the outliers using this technique if you notice that some people spending considerably more or less than your average customer. Heterogeneous Case Sampling: As a preliminary-phase market research option known as maximum variation sampling, heterogeneous sampling is a type of purposive sampling method aims to interact a wide array of subjects to have a view of the general public. Use this research technique to help you examine how people recognize your brand and if they associate your brand identity like your logo with the products they sell and to determine groups that are aware of your brand and groups that should be targeted more efficiently. Homogenous Case Sampling: Being the opposite of heterogeneous case sampling, researchers use this type of purposive sampling method when they choose shared characteristics to determine and examine a sampling group. Carry out this research methodology if you need to measure the shared interest among specific audiences. Typical Case Sampling: It is a type of purposive sampling that is beneficial when researchers are investigating a specific phenomenon or trend. They use this research technique to compare what is considered typical or common for members of a population. Apply this research methodology if your research and development team needs to examine how a product or trend made an impact on the average customer. Total Population Sampling: Want to disintegrate large audiences into manageable options based on each of their classifications? Apply this type of purposive sampling if you selected a target population sharing one or multiple characteristics in your research study. Set specialized categories based on your target audience.

Benefits of Purposive Sampling

There are many uses of purposive sampling in various fields and industries. For example, purposive sampling is extensively used for market research, brand development research, product research, and quality development plans. What are the notable benefits of using purposive sampling?

1. Higher Quality Information

Purposive sampling is a beneficial research methodology that gives higher-quality information because it focuses on a small case study. This means the information collected and analyzed for the research using this technique is specific to the needs of the researchers as they fully filter out response bias. So, it helps you to target niche demographics to acquire specific data for your research study.

2. Time and Cost Efficiency

It is one of the most cost-efficient and time-efficient sampling methods available for researchers. They use this research technique to select suitable participants for their in-depth investigation based on their knowledge. Use this research methodology to make the most out of a small population of interest without the need to spend lots of time and money. 

3. Increased Quality of Responses

Due to the ability of the researchers to collect plenty of data from a smaller number of committed respondents, purposive sampling is a great research tool to obtain top-quality responses. It leads to deep insights and more accurate research outcomes. 

4. Narrow the Margin of Data Error

Researchers who apply purposive sampling narrow the margin of error because the specific criteria established as the best-fit candidates make the cut for their research studies. The collected information will be entirely valuable to the study, more precisely reflective of the audience, and the outcomes are relevant to the research context.

How to Create a Purposive Sample

If you aim to focus in-depth on a particular phenomenon or trend, use purposive sampling and create a purposive sample for your study. Take note of this step-by-step guide to create a purposive sample properly.

Step 1: Identify Your Research Problem

What is your research problem? Is it a certain challenge, issue, or gap in the knowledge you want to address in your case study? Formulate your research problem so that cane to know the next steps in your research design, especially on what type of sampling technique and analysis you will carry out.

Step 2: Define Your Population

Describe the population clearly in which your sample will be collected. For example, determine their ages, cultural backgrounds, and other demographic factors vital to your research.

Step 3: Elaborate on the Characteristics

Explain the specific characteristics or experiences of the members of the population in your purposive sampling. It helps you to choose the individuals or cases that align with your research study.

Step 4: Collect Data

Decide which data collection method is appropriate to your research study. Consider how much data you need to collect as well. Use data collection sheets while gathering the data you need for your work.

Step 5: Develop a Comprehensive Analysis

Then, analyze and interpret the results of your purposive sampling. Record the research bias in the methodology part of your research paper. Avoid making any interpretations apart from the sampled population.

FAQs

Why is purposive sampling used?

Purposive sampling is a research methodology that allows researchers to extract more information from the data that they have gathered. This technique enables them to describe and explain the crucial impact their findings have on the population.

What are the common ways to get a sample?

The common ways to get a sample for your research study are convenience sampling, systematic sampling, stratified sampling, random sampling, quota sampling, and purposive sampling.

What type of study uses purposive sampling?

Qualitative research is the type of study that uses purposive sampling as it aims to identify and select information-loaded cases linked to the phenomenon of interest.

How to determine the sample size for purposive sampling?

The researchers who use purposive sampling or a sample size calculator are free to select a sample size that they think has the best characteristics appropriate to provide them with all-inclusive and in-depth quality information on what they are researching and studying.

What is the difference between purposive sampling and random sampling?

Purposive sampling is a non-probability sampling method used to select a purposive sample based on the characteristics of a population and the main objective of the study. While random sampling is a sampling method in which researchers use a subset of individuals or a sample chosen from a larger set or a population.

Can I use purposive sampling in quantitative and qualitative research?

If you need to conduct a study on a specific cultural domain with well-informed professional experts within, you can use purposive sampling with both qualitative and quantitative research methodologies. 

What are the limitations of purposive sampling?

Purposive sampling has some drawbacks or limitations. It may exclude fundamental subgroups from the research study accidentally or by design. It may not be effective on a large scale as it is best used for smaller groups and specific niches. There are data invalidation risks due to subgroup exclusion and the researchers using this sampling technique are at a greater risk of having an extreme bias in their candidate selection.

How do you select respondents in purposive sampling?

To select respondents in purposive sampling, you carefully choose those community members who you consider will give you the best information for your case study analysis work. 

If you need to describe the fundamental impact of your research findings on a specific group or population while being time and cost-efficient, purposive sampling might be the best non-probability sampling technique for you. It is a unique and versatile research methodology often used in qualitative research to allow the researchers to gain detailed knowledge about a specific phenomenon. Plus, this research tool can be tailored to bring the effectiveness of your survey research to the next level. Sample.net provides a variety of PDF templates for purposive sampling, cluster sampling, systematic sampling, and other probability sampling methods that you can easily access and download for your research and data analysis projects.