Understanding and Applying Research Design

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LEARNING FROM POPULATIONS: CENSUSES AND SAMPLES

Social scientists are often concerned with populations. One of the hallmarks of social research is precision; researchers must be very precise when defining concepts. Unfortunately, for many of the concepts we use there is a popular usage of terms that mistakes the very precise definition scientists must use. Generally when using the word population, what comes to mind is the population, meaning the population of a nation (and more specifically our nation). When social scientists use the word population, the population may not include any people at all. A scientific population contains all units of a set (sometimes referred to as a universe). So if we’re interested in the population of the United States, every single person in the United States is part of the set/universe. If we are interested in how fourth grade teachers in the state of Washington prepare their students for the state exam, all fourth grade teachers in the state of Washington are the population. If we are interested in how themes in pop songs from the 1960s differ from pop songs of the 2000s, then all pop songs from both decades would be the population of interest (of course, we would also need to define what counts as a “pop” song before we would want to collect songs from either decade). Researchers determine a population based on their research question and design. Depending on their goals or the size of the population, researchers can choose to collect data ...