Snowball sampling

Snowball sampling

Snowball sampling is a non-probability sampling technique where existing study subjects recruit future subjects from among their acquaintances. Thus, the sample group appears to grow like a rolling snowball. As the sample builds up, enough data are gathered to be useful for research. This sampling technique is often used in sociology and statistics research.

Methodology

Snowball sampling begins with a small pool of initial informants. These initial subjects are selected through a non-random sampling method. Each of these subjects is then asked to nominate other individuals who meet the criteria for inclusion in the study. This process continues until the sample size is sufficient or until no new subjects are identified.

Advantages

• **Access to hidden populations**: Snowball sampling is particularly useful for accessing populations that are difficult to reach or identify, such as drug users, sex workers, or individuals with rare diseases.
• **Cost-effective**: This method can be more cost-effective than other sampling techniques, as it relies on the social networks of initial subjects to recruit additional participants.
• **Efficiency**: Snowball sampling can be quicker to implement than other sampling methods, especially when the target population is hard to locate.

Disadvantages

• **Bias**: The sample may not be representative of the broader population because it relies on the social networks of the initial subjects. This can introduce selection bias.
• **Lack of randomness**: Since the sample is not randomly selected, the results may not be generalizable to the entire population.
• **Dependence on initial subjects**: The quality and diversity of the sample heavily depend on the initial subjects chosen.

Applications

Snowball sampling is widely used in various fields, including:

• Sociology: To study hidden or hard-to-reach populations.
• Public health: For researching the spread of diseases within specific communities.
• Market research: To understand niche markets or consumer groups.

Related Pages

• Sampling (statistics)
• Non-probability sampling
• Selection bias
• Sociology
• Public health

See Also

• Chain referral sampling
• Respondent-driven sampling
• Convenience sampling