Which sampling approach is described as potentially biased due to opportunity and self-selection?

Which sampling approach is described as potentially biased due to opportunity and self-selection?

• A. EPSEM
• B. Non-random sampling techniques
• C. Opportunity sampling
• D. Stratified sampling

Answer: (C)

The idea being tested is how the way participants are chosen can introduce bias. Opportunity sampling selects anyone who is available and willing to take part at the time, so participants self-select by their availability and interest. This can lead to a sample that differs in important ways from the broader population, reducing generalizability because the volunteers may share traits (motivation, interest, time availability) that aren’t representative of everyone the study aims to understand. Think of it as a quick, convenient method that sacrifices representativeness. By comparison, methods that aim for equal chances of selection or deliberate representation of subgroups work to reduce bias, while non-random techniques cover a range of approaches that can still be biased. The specific mechanism described here—choosing from those who are readily around and willing to participate—defines opportunity sampling.

The idea being tested is how the way participants are chosen can introduce bias. Opportunity sampling selects anyone who is available and willing to take part at the time, so participants self-select by their availability and interest. This can lead to a sample that differs in important ways from the broader population, reducing generalizability because the volunteers may share traits (motivation, interest, time availability) that aren’t representative of everyone the study aims to understand.

Think of it as a quick, convenient method that sacrifices representativeness. By comparison, methods that aim for equal chances of selection or deliberate representation of subgroups work to reduce bias, while non-random techniques cover a range of approaches that can still be biased. The specific mechanism described here—choosing from those who are readily around and willing to participate—defines opportunity sampling.