Advanced Research Methodology – Session 6: Sampling and Sampling Techniques

This lecture focuses on sampling theory and sampling techniques as core methodological components of rigorous research design. It is designed for clinicians, public health professionals, and medical or nursing students who already have foundational engagement with research methodology and are in the process of finalizing research proposals or scientific manuscripts.

The session begins by clarifying fundamental concepts, including population, sample, and sampling frame, and emphasizes their correct definitions and alignment with research objectives. Common conceptual and reporting errors related to population definition and sampling frame selection are discussed.

The lecture then provides a structured overview of probability sampling techniques, including simple random sampling, systematic sampling, stratified sampling, and cluster sampling, with attention to their assumptions, advantages, limitations, and applicability in clinical and public health research settings.

In addition, the session addresses non-probability sampling techniques, such as convenience, purposive, quota, and snowball sampling. Emphasis is placed on appropriate justification, potential sources of bias, and transparent reporting when non-probability methods are used.

Throughout the lecture, sampling decisions are explicitly linked to study validity, generalizability, and interpretation of findings, supporting learners in making defensible methodological choices during manuscript preparation.

Intended audience: Clinicians, public health researchers, medical and nursing students, early-career health researchers
Resource type: Teaching and learning material (lecture slides)