Another important decision is what is our universe or population, composed of people (in a study of electoral behavior, for example, the set of voters; in a study of audiences, people who follow a particular medium or program) or objects (the set of episodes of a television series that constitutes our object of study, or of the news on a specific subject that we must analyze). In the technique of content analysis it is also called corpus and its manufacture requires a series of steps that we will explain in due course. Once the problem has been defined, the hypotheses have been formulated and the variables have been identified, it is necessary to delimit what is part of the universe or population. If we can observe all the units that make up the universe (= a census) or if it is a part of the universe (= the sample). The census is a feasible option for small universes.

The hypothetical universe is the totality of the set of elements, beings or objects that are tried to investigate. It includes all existing populations on which research could be conducted.

The population is the set of all cases coinciding with a series of specifications. Your units must be of the same nature as the sample. The sample, therefore, is a subgroup of the population.