I have a pivot table with a bunch of columns indicating the value over time, and would like to create a calculated field showing the change over each value. How would I reference the previous (and next) column's value in the calculated field in the pivot table?
According to Google Sheets documentation, available here, you can use the names of the previous and next fields to customize your calculated field formula.
You can use other columns to write a formula. For example, you can use =sum(Price)/counta(Product) where "Price" and "Product" are fields in the pivot table.