Grids
Categorical grid
Numeric grid
A grid is a special case of a loop, in which the iterations are controlled by a category list and when the grid question is asked, all of the iterations are presented simultaneously. In the Museum survey there is a grid question that asks respondents to rate the galleries in the museum:
Rating grid question
In this grid, the list of galleries is the controlling category list, the grid itself is called rating and the categorical question inside the grid is called column. The full names of the individual variables that store the flattened responses to the grid are:
rating[{Dinosaurs}].Column
rating[{Conservation}].Column
rating[{Fish_and_reptiles}].Column
rating[{Fossils}].Column
rating[{Birds}].Column
rating[{Insects}].Column
rating[{Whales}].Column
rating[{Mammals}].Column
rating[{Minerals}].Column
rating[{Ecology}].Column
rating[{Botany}].Column
rating[{Origin_of_species}].Column
rating[{Human_biology}].Column
rating[{Evolution}].Column
rating[{Wildlife_in_danger}].Column
rating[{Other}].Column
These are sometimes referred to as grid slices.
When the question or questions inside the grid are numeric rather than categorical, the grid is sometimes referred to as a numeric grid question. For example, in the Short Drinks sample data, there is a numeric grid question that asks respondents to enter the number of drinks of various types they consumed each day of the previous week:
Numeric grid question
In this example, the drinks are the iterations and the days of the week are numeric questions inside the loop.