Always Define Deliverables and Acceptance Process
Have you ever had a supplier send you an invoice based on a payment schedule and a statement of work, but had no way of knowing if that work was ever completed - or if the deliverables were to the satisfaction of your business unit?
If your statement of work didn’t have clearly defined deliverables or an acceptance process for those deliverables, then the chances are there isn’t much you could about it – except pay the invoice and hope they did a good job.
But it should never be that way with professional services.
Any time you negotiate a statement of work with a professional services provider - whether it’s for a fixed-cost engagement or time and materials - you should always have clearly defined deliverables with milestones, an acceptance process for each deliverable, and payment terms tied to the acceptance of those deliverables.