Background and objectivesThere is now a wide variety of methods available to general practitioners who want to engage in quality assessment, quality assurance, or quality improvement activities in their practices. These methods require some kind of performance review, or at least the collection of some performance-related data. As in traditional research, the choice of methods depends on what research questions one wants to address. This paper elaborates on some key concepts related to the choice of methods, making a distinc tion between whether any method actually covers performance (what a doctor does in daily practice) or competence (what a doctor is capable of doing) as well as a distinction between whether a method is direct (patient-doctor contact is observable) or is indirect.MethodsAn overview frame will be presented of the methods most commonly used for data collection within quality assessment. These methods are discussed on their validity, reliability, feasibility and acceptability. Direct methods aimed at recording performance are assumed to hold the highest validity, but practical, economic and logistic factors may favour less ambitious methods for audit or quality improvement activities.ConclusionsOne crucial element in all methods is creating a set of empirical data, as a basis for comparisons, reflection, dialogue and discussions among colleagues.