Based on a few more complex process maturity assessments I have attempted a simplified mash-up which you can view and download here (or see the preview below): https://docs.google.com/spreadsheets/d/1idNgFP6YG-PLev8WdtgvWHKC7Il0y9_h1BZrmfko8NY/edit?usp=sharing
It is still not simple, as it covers many aspects, but the format is a basic list that anyone can complete fairly easily. You can decide whether to rate each criterion (light-grey rows) which will automatically calculate a score per category (dark-grey rows). Or you can directly enter a rating for the overall categories (blue-green rows).
Business Process Management 