When a sample is obtained by asking a participant, who is initially selected in the sample, to suggest some one else who might be willing or appropriate for study, the sample is labelled as

Question

Prepp Team · Accepted Answer

Understanding Sampling Methods in Research

Research studies often require selecting a group of individuals or items from a larger population to gather data. This process is known as sampling. The way a sample is obtained significantly impacts the reliability and generalizability of the research findings. Different research questions and populations call for different sampling techniques.

Identifying the Snowball Sampling Technique

The question describes a specific method of obtaining a sample where initially selected participants are asked to recommend other potential participants. Let's analyze this method based on the provided options:

The process starts with a small number of initial participants.
These participants then identify and recruit further participants from their network.
This referral process continues, potentially increasing the sample size like a rolling snowball gathering more snow.

This description aligns perfectly with the characteristics of a method called snowball sampling. It's a non-probability sampling technique often used when studying populations that are difficult to access or identify, such as individuals with specific rare diseases, hidden populations, or members of particular social groups.

Comparing Sampling Methods

Let's briefly look at the other options to understand why they are not the correct answer for the described method:

Sequential Sample: This often refers to a sampling technique where data is collected from any available subject that meets the inclusion criteria until the required sample size is reached or certain statistical criteria are met. It doesn't involve participants referring others.
Purposive Sample: Also known as judgmental sampling, this is a non-probability technique where the researcher uses their expertise or judgment to select participants who are considered most appropriate or knowledgeable for the study's purpose. It does not rely on referrals from initial participants.
Consecutive Sample: Similar to sequential sampling, this involves selecting all subjects who meet the inclusion criteria and are available during a specified time period or until the required sample size is reached. It's a type of non-probability sampling often used in clinical studies. It doesn't involve a referral chain.

Based on the mechanism described in the question, where initial participants suggest others, snowball sampling is the accurate term for this sampling method.

Why Snowball Sampling Fits the Description

In snowball sampling, the researcher begins with one or a few individuals who meet the study's criteria. These initial contacts are then asked to identify other potential participants who also meet the criteria. This chain of referrals continues until the desired sample size or data saturation is reached. This technique is particularly useful when a list of the target population is unavailable or when potential participants are reluctant to come forward. The trust within existing networks helps in accessing otherwise hidden populations.

Therefore, the sampling method where participants recruit others is definitively snowball sampling.

Sampling Method	Description	Referral Mechanism?
Snowball Sample	Initial participants refer other potential participants.	Yes
Sequential Sample	Select available subjects until criteria met or size reached.	No
Purposive Sample	Researcher selects based on judgment.	No
Consecutive Sample	Select all available subjects over a period.	No

Revision Table: Key Sampling Concepts

Term	Brief Explanation
Sampling	Selecting a subset of a population for study.
Population	The entire group the researcher is interested in.
Sample	The selected subset of the population.
Probability Sampling	Each member of the population has a known, non-zero chance of selection (e.g., Simple Random, Stratified).
Non-Probability Sampling	Selection is not based on random chance (e.g., Snowball, Purposive, Convenience).

Additional Information on Snowball Sampling

While useful for specific populations, snowball sampling has limitations. The sample obtained may not be representative of the entire population, as it relies on existing social networks. Participants are likely to refer people they know, who may share similar characteristics, potentially introducing selection bias. The researcher has limited control over the sample composition. However, for exploring sensitive topics or reaching marginalized groups, it can be an invaluable technique.