Summary: Among the many challenges of conducting a Public Expenditure Tracking Surveys (PETS) in difficult environments, this study highlighted the challenges relating to data availability and security. For example, the extent to which the flow of funds is straightforward can make the difference between an effective and an ineffective PETS. Even a carefully-designed PETS questionnaire can yield minimally useful results if expenditure data from various sources cannot be triangulated either because it is not documented, or it is not documented uniformly. In addition, insecurity could pose a significant threat to the validity and reliability of sample data unless the presence of corruption is assumed to be unrelated to security in regions where budget units are located. In light of these challenges, this paper assesses the strengths and weaknesses of various mechanisms to tackling corruption and making PETS work.