The following procedure describes how to create a constant date metric (i.e. 1/1/2010) that can be used to perform date time functions.
1. Create a new metric with the following format: Max(‘DD/MM/YYY') {~}.
2. In the metric editor, go to Tools > Formatting > Values and change the number format to “Date”.
The results of these steps are shown in the screenshot below:

This newly created metric can now be used to perform date calculations of the user’s choice.