This chapter focuses on a different type of project activity risk, risk events that may or may not occur. It examines the treatment in project risk analysis of the class of risks that is sometimes called 'risk events'. The exciting characteristic of these risks is that they have a probability of less than 100 percent of existing and therefore are either included in the schedule or not. Qualitative risk analysis takes identified risks and assesses their: The probability of a risk's occurring and its impact if it were to occur are assessed by interviewing people knowledgeable in the project. The chapter explores the most likely durations that are those deterministic durations in the schedule but there are optimistic and pessimistic durations that should be considered. Each of these tests may fail, and introduce in a cumulative way.