Non-probability sampling: Convenience Sampling

• Non-probability sampling includes convenience, purposive, and snowball sampling methods.

Convenience Sampling

• Most common sampling method where participants are readily available due to access, location, time, and willingness.
• Simply involves individuals most accessible to the researcher.
• Useful for getting a sense of people's attitudes and opinions.
• Useful for running a test pilot for a survey.
• Useful for generating hypotheses for future, in-depth research.
• Samples are biased, not statistically balanced selections of the population, as the researcher draws the sample based on ease.
• Monetary or other incentives may lead to inaccurate or false answers if that's the participant's only motivation.
• Researcher subjectivity in participant selection introduces bias; for example, picking the "friendliest" passersby.
• Reduce bias by detailing recruitment in the methodology section to allow reproducible studies.
• Diversify data collection by including more participants and using a sample size calculator.
• Distribute surveys at various times and using different recruitment strategies.
• Avoid exaggerating research findings.
• Low-cost and easy, with readily available subjects.
• Allows data collection without a sampling frame that would otherwise be impossible.
• Accuracy of data and the risk of missing important cases can lead to under coverage bias.
• Accuracy relies on the researcher's subjective judgment of the participants and their motivations.

Purposive Sampling

• A frequently used sampling strategy where participants are recruited based on generation, time periods, or content.
• Researcher uses judgment in selecting members for the study.
• The sample group is targeted to have specific attributes.
• Easier to generalize the sample versus a random sample.
• Cost-effective and produces substantial results quickly.
• Helps in avoiding sampling errors.
• Bias is possible because participants know they are part of the project

Snowball Sampling

• Also known as chain referral or networking sampling.
• Begins with gathering information from a few people, who then connect the researcher with their friends, relatives, colleagues, or contacts.
• Useful for researching populations not easily accessible.
• Starts with one or more study participants.
• Useful for studies regarding people with specific traits that are difficult to identify (e.g., people with a rare disease).

Convenience sampling is a non-probability method where participants are readily available. Useful for preliminary research and hypothesis generation. Samples are biased, therefore researchers should be aware of its limitations.