Create a Consistent Structure for Calculations
When spreadsheets are created ad-hoc, the usage of time steps tends to be inconsistent: advancing by rows in one sheet, columns in another, and even a mix of the two in the same sheet. Sometimes steps will be weeks, other times months, quarters, or years. This is confusing for users and reviewers, leads to low trust, increases the time for updates and audits, and adds to the risks of the spreadsheet.
A better way is to make all calculations follow a consistent layout, either across rows or columns, and use that layout for all calculations, regardless if it requires a few more rows or columns. For example, one way to make calculations consistent is with time steps going across the columns and each individual calculation going down the rows:
Author(s): Stephan Mathys
Publication Date: June 2021
Publication Site: Small Talk at the Society of Actuaries