The most variable metric law department managers track is outside counsel spending. This got me wondering whether there is much seasonality to the inflow of invoice amounts: Are there any patterns by month for how much gets billed to law departments?

A priori, one might suppose that the need for external legal services shows a reasonable consistency during the course of a year, and that invoices arriving for those services, albeit delayed, match that consistency.

Some perturbations do, however, seem likely. Many retailers see their revenue clump into the end-of-year holiday period. And, of course, there are climate-based businesses–think ski lodges and water-skis. It is also reported that some deals are aggressively pushed toward the end of a company's fiscal year. Even so, the invoices of the law firms that work on those deals will not arrive until a month or so later.