How to Compare the Current Row to the Previous Row in Power Pivot

In this post, Dany demonstrates how we can use Power Query to add a numerical index column to our table, and then use that to address the previous row in a calc column. Lots of good stuff here. More generally, this is achievable using the misleadingly-named EARLIER function. EARLIER does not mean "previous row," but coincidentally, you can use it to do just that, and many other "cross-row reference" things. Check out this post on EARLIER for the basics (or read the calc column chapter in Power Pivot Alchemy), and read some of the comments at the end of this post for further examples.