# Crosstabs Involving Date Questions

The table below shows a crosstab of a Number question, NPS, by a date question.

By default, with time series data Q compares to all the other time periods (see Testing the Complement of a Cell). For example, the significant red arrow for January 2011 is telling us that the NPS for that month is below the overall average.

Q can also be instructed to compare each month to the previous month. This is done by selecting **Compare to previous period** in the Date questions setting in Statistical Assumptions). This is illustrated in the table below.

## See also

- Independent Sample Tests - Comparing Two Proportions and Independent Sample Tests - Comparing Two Means for a discussion of how Q computes tests on such tables.