How do I measure return on my channel investment?

Begin with the investment in staff to manage channel partners, which can be attributed 100% to your cost of channel. Add to that all investments in market development funds for partner marketing activities, events, collateral, and other campaign costs. Be sure to include any additional costs for partner recruiting, onboarding, training, and support. Then simply subtract that from total sales coming from partners. Since you are not paying a salary or draw to partners as you would to direct salespeople, the calculations are far simpler. The challenge, as always, is in accurately and thoroughly capturing your entire cost burden.