Chapter 6: Sampling

If you were to see a cute photo of babies hanging out together and one of them was wearing a green onesie, if you were to conclude that all babies wore green based on the photo that you would have committed selective observation. In that example of informal observation, our sampling strategy (just observing the baby in green) was of course faulty, but we nevertheless have engaged in sampling. Sampling has to do with selecting some subset of one’s group of interest (in this case, babies) and drawing conclusions from that subset. How we sample and who we sample shapes what sorts of conclusions we are able to draw. Ultimately, this chapter focuses on questions about who or what you want to be able to make claims about in your research. In the following sections, we’ll define sampling, discuss different types of sampling strategies, and consider how to judge the quality of samples as consumers of social scientific research.

LEARNING OBJECTIVES

• Understand the difference between populations and samples.
• Define nonprobability sampling, and describe instances in which a researcher might choose a nonprobability sampling technique.
• Describe the different types of nonprobability samples.
• Describe how probability sampling differs from nonprobability sampling.
• Define generalizability, and describe how it is achieved in probability samples.
• Identify the various types of probability samples, and provide a brief description of each.
• Identify several questions we should ask about samples when reading the results of research.
• Name some tenets worth keeping in mind with respect to responsibly reading research findings.