A social work researcher selects every 3rd client on a list for a study. What type of sampling is this?

The type of sampling described is systematic sampling. In this method, researchers select participants based on a fixed interval from a list or a population. In the scenario presented, every 3rd client is chosen, which exemplifies this technique. The systematic approach allows for a structured way to select samples, reducing biases that can arise from random selection while ensuring each member has an equal chance of being selected according to the interval set.

In systematic sampling, the researcher first determines a sampling interval, which in this case is 3, and then selects every third client from an ordered list. This method can be particularly advantageous when researchers have a comprehensive list and need a manageable way to gather a sample without the variability of a fully random selection.

Other sampling methods mentioned, such as simple random sampling, cluster sampling, and stratified sampling, have different protocols that do not involve the fixed interval selection characteristic of systematic sampling. Simple random sampling involves selecting subjects entirely at random without any specific order or system, cluster sampling involves dividing the population into clusters and randomly selecting entire clusters, and stratified sampling involves dividing the population into subgroups and then randomly sampling from those groups. These differences set systematic sampling apart and clarify why it is the correct response.