Sampling Design in Social Science Research

Sampling Design

By Hadijah Jaffri

Introduction to Sampling Design

Sampling design refers to the plan or strategy used to select a subset (sample) from a larger group (population) to participate in a study.

In educational research, sampling helps generalize findings from a sample to the broader educational population for quantitative research approach..

Factors to Consider in Sampling Design

• Research objective (e.g., generalization vs. in-depth understanding)

• Population accessibility

• Time and resources

• Desired level of precision

• Ethical considerations

Term	Definition
Population	The entire group the researcher wants to study (e.g., all secondary school students in Malaysia).
Sample	A subset of the population selected for the study.
Sampling Frame	A list or database from which a sample is drawn.
Sampling Unit	An individual or group being studied (e.g., student, teacher, school).

Multiple Choice

When is the appropriate time to decide your samples in your research?

• During the planning phase of your research.
• When writing the final report.
• During the analysis phase of your research.
• After data collection is complete.

Type of sampling design: Probability sampling

Probability sampling is a sampling technique where every individual in the population has a known and equal chance of being selected. This method reduces bias and allows researchers to generalize results to the larger population with greater confidence. Examples include simple random sampling, stratified sampling, cluster sampling, and systematic sampling.

Types of probability sampling

• Simple Random Sampling: Every individual in the population has an equal chance of selection. It is straightforward but requires a complete list of the population.

• Stratified Sampling: The population is divided into subgroups (strata) based on specific characteristics (e.g., gender, education level), and random samples are drawn from each group. This ensures diversity and representation.

Types of probability sampling

• Cluster Sampling: Groups or clusters (e.g., schools, neighborhoods) are randomly selected, and all individuals within selected clusters are included. This is useful for large or geographically spread populations.

• Systematic Sampling: Researchers select every k-th person from a list (e.g., every 5th student on a roster). It’s simpler than random sampling but requires careful ordering.

Type of sampling design: Non Probability sampling

Non-probability sampling is a sampling technique where not all individuals in the population have a known or equal chance of being selected. It is often used when random selection is not possible or practical. This method may introduce bias but is useful for exploratory research or when studying specific groups. Examples include convenience sampling, purposive sampling, quota sampling, and snowball sampling.

Types of non probability sampling

• Quota Sampling: Similar to stratified sampling but without random selection; researchers select a set number of participants from certain groups.

  Example: Selecting a sample of 100 students while maintaining the same grade-level ratio as the overall population. First year and second students: 80% of 100 = 80 students, third year students: 15% out of 100 = 15 students, fourth year students: 5% of 100 = 5 students.

• Snowball sampling: Used for hard-to-reach populations, where existing participants refer others who meet the criteria.

  Example: Asking a participant to recommend another participant with similar criteria

Types of non probability sampling

• Convenience Sampling: Participants are selected based on availability and ease of access. While practical, this method may introduce bias.

  Example: Asking anyone on Facebook to answer questionnaire about study habits

• Purposive Sampling: Researchers deliberately select individuals based on specific traits or experiences relevant to the study.

  Example: Selecting Dean's list students to explore their study habits

Applications in Educational Research

Research Question	Suggested Sampling Design
What is the average reading score of Year 6 students in Malaysia?	Stratified random sampling by region and school type
How do gifted students experience classroom learning?	Purposive sampling of gifted students
What are students’ attitudes towards online learning during a school closure?	Cluster sampling of selected schools or classes

Match

Match the following sampling design

• Convenience Sampling

• Purposive sampling

• Cluster sampling

• Snowball sampling

• Stratified sampling

Non probability sampling

Non probability sampling

Probability sampling

Non probability sampling

Probability sampling

• Non probability sampling

• Non probability sampling

• Probability sampling

• Non probability sampling

• Probability sampling

Common Mistakes to Avoid

• Using too small or unrepresentative samples for quantitative research

• Ignoring potential biases in non-probability sampling

• Overgeneralizing results from convenience samples

Dropdown

​

Select answer

is the entire group the researcher wants to study (e.g., all secondary school students in Malaysia), whereas ​

Select answer

is a subset of the ​

Select answer

selected for the study.