To have confidence in the results of an archaeological survey, whether for heritage management or research objectives, we must have some assurance that the survey was carried out to a reasonably high standard. This paper discusses the use of Quality Assurance (QA) approaches and empirical methods for estimating surveys' effectiveness at discovering archaeological artifacts as a means for ensuring quality standards. We illustrate with the example of two surveys in Cyprus and Jordan in which resurvey, measurement of surveyor "sweep widths," and realistic estimates of survey coverage allow us to evaluate explicitly the probability that the survey missed pottery or lithics, as well as to decide when survey has been thorough enough to warrant moving to another survey unit.