Improving the quality of care at hospitals is a key next step in rebuilding Liberia’s health system. In order to improve the efficiency, effectiveness, and quality of care at the secondary hospital level, the country is developing a system to upgrade health worker skills and competencies, and shifting towards improved provider accountability for results, including a Graduate Medical Residency Program (GMRP) and provider accountability for improvements in quality through performance-based financing (PBF) at the hospital level. This document outlines the protocol for the impact evaluation of the hospital improvement program. The evaluation will provide an estimate of the impact of the project and investigate the mechanism for success in a way that can provide general lessons about the quality of health care in low-income countries. The evaluation aims 1) to provide the best possible estimate of program impact and 2) to quantitatively describe the changes that took place within facilities as a result of the program. In particular, the impact evaluation focuses on the changes in human resources within the hospitals. As such, we use a three-period intensive evaluation of treated and matched comparison hospitals to see how services change in treated hospitals as well as a continuous data collection effort to track the activities of individual health workers within treated hospitals.