Surveys and questionnaires often contain individual questions and sets of questions that are asked more than once. For example, questionnaires often contain grid questions that ask respondents to choose a rating on a predefined scale for a number of products in a list, and sets of questions that respondents are asked to answer for each product in a list of products or for each person in a household. The data collected using these types of constructions is sometimes referred to as hierarchical data.

For an introduction to hierarchical survey structures, see Loops and grids. This section contains additional information about how to work with hierarchical data in UNICOM Intelligence Reporter, and also provides information about working with grid and loop slices when you are using the flat view.

All examples in this section use the Household XML Sample data set. See The Household sample for more information.