This is the unit—for example individual, household, corporation, or whatever—about which information is required in a research project. Students often confuse the unit of enquiry (sometimes also called the unit of analysis) with the sampling unit. The two need not be the same for any particular study. Thus, one may sample households, and then collect information (from one or more of its members) about all individual residents. Here, the sampling unit is the household, and the unit of enquiry is the household member.