Calculations that make comparisons to previous quarters or to the same period one year ago are very important in all business intelligence tools. DAX, the formula language in PowerPivot, allows you to define such calculations by means of Time Intelligence Functions . However, in order to use these, you need to include a Date dimension table in your PowerPivot model. When you do not have access to a date table in your ICT network, you will be able to create one on the spot after reading this post.