Analysis levels are a relatively easy way of processing hierarchical data with or without trailer cards. Each analysis level is a field of columns, a card or set of cards containing information for a specific level in the data hierarchy. For example, if card 1 contains information about the household as a whole, and each card 2 stores data for a different person in that household, you have two levels, one for the household and one for people within the household.

You can edit and tabulate data by level by giving each level a name and applying it to the edit and tabulation statements for that level. A maximum of nine levels is allowed.

You can name levels and define the structure of the levels data either using a standard struct statement with some additional parameters for levels, or using a levels file. Both methods are described below.