Business Process Re-engineering (BPR) inevitably involves change. However, modern business organizations are extremely complex. Setting improvement targets in BPR too high without considering the company’s capability and its external and internal interactions will have little chance of achieving the set targets, which means project failure. Unfortunately, forecasting of the BPR outcomes is currently a wild guess to management. This paper describes a risk model that estimates a process improvement capability score and integrates with a performance effectiveness function to assess the likelihood of meeting performance gain targets from process improvement projects undertaken by companies. The risk assessment can assist management to set more realistic performance gain targets for process improvement projects with a better chance of success.