To draw attention to changes over time and make a trend report, you can add significance testing in a crosstab by clicking on the 'Sgn' button in the metrics toolbar.

To manage Significance settings click on the down arrow next to the 'Sgn' button and open the Comparison pop-up

Here you can manage the final appearance of the Significance indicators. If you need to compare data not with the previous, but with the earlier period, make a bigger shift (2, 3 or more).

Here you also may find additional significance settings. For instance, here you can manage the significance thresholds.