Definition of Acceptance Plan??An agreed-upon method of taking samples and making measurements or observations on these samples for the purpose of evaluating the acceptability of a lot of material or construction (Transportation Research Circular Number E-C037@ 2002). Purpose of Acceptance Plan??This standard practice provides guidelines in the preparation of statistically based acceptance plans using statistical and quality assurance (QA) principles. The acceptance plans must be realistic@ fair to both the contractor and agency@ and statistically accurate. This standard practice includes the basic criteria for the most common AASHTO applications. It uses the broad definition of acceptance plan to include the separate functions of both quality control (QC) and acceptance. Other aspects are provided where deemed important@ but should not be interpreted to define a complete QA program. References are given for more advanced criteria and special applications. Target Audience??It is assumed that the user is a mid-level materials engineer and has an understanding of statistics@ including the calculation of the mean and standard deviation@ the development of histograms@ and the use of continuous probability density functions or distributions. Background Sources??Preparatory knowledge of acceptance plans is included in the course entitled Materials Control and Acceptance??Quality Assurance (2000); in the manual Optimal Procedures for Quality Assurance Specifications (2003); and in most basic statistics textbooks.