An optimization-based approach for designing attribute acceptance sampling plans Belmiro P.M. Duarte Departamento de Engenharia Quı ´mica e Biolo ´gica, Instituto Superior de Engenharia de Coimbra and GEPSI-Grupo PSE, CIEPQPF, Departamento de Engenharia Quı ´mica, Universidade de Coimbra, Coimbra, Portugal, and Pedro M. Saraiva GEPSI-Grupo PSE, CIEPQPF, Departamento de Engenharia Quı ´mica, Universidade de Coimbra, Coimbra, Portugal Abstract Purpose – This purpose of this paper is to present an optimization-based approach to support the design of attribute sampling plans for lot acceptance purposes, with the fraction of non-conforming items being modeled by a Poisson probability distribution function. Design/methodology/approach – The paper approach stands upon the minimization of the error of the probability of acceptance equalities in the controlled points of the operating curve (OC) with respect to sample size and acceptance number. It was applied to simple and double sampling plans, including several combinations of quality levels required by the producer and the consumer. Formulation of the design of acceptance sampling plans as an optimization problem, having as a goal the minimization of the squared error at the controlled points of the OC curve, and its subsequent solution employing GAMS. Findings – The results are in strong agreement with acceptance sampling plans available in the open literature. The papers approach in some scenarios outperforms classical sampling plans and allows one to identify the lack of feasible solutions. Originality/value – An optimization-based approach to support the design of acceptance sampling plans for attributes was conceived and tested. It allows for a general treatment of these problems, including the identification of a lack of feasible solutions, as well as making possible the determination of feasible alternatives by relaxing some model constraints. Keywords Acceptance sampling, Poisson distribution, Non-linear control systems, Quality assurance Paper type Conceptual paper 1. Introduction and motivation Quality assurance has emerged in the past decades as one of the keystones in supplier-customer relationships (Evans, 2005). Its main goal is to provide customers with evidence that products do indeed reach the quality levels required and agreed upon. Acceptance sampling is related with inspection and decision making regarding product quality, and is indeed one of oldest subjects covered by statistical quality control (Montgomery, 2001). Acceptance sampling is applied as an auditing tool, in order to check whether products have or not met the quality levels required. It is thus mostly focused in product quality auditing, rather than process improvement (Mitra, The current issue and full text archive of this journal is available at www.emeraldinsight.com/0265-671X.htm IJQRM 25,8 824 Received 9 December 2007 Revised 10 April 2008 Accepted 22 April 2008 International Journal of Quality & Reliability Management Vol. 25 No. 8, 2008 pp. 824-841 q Emerald Group Publishing Limited 0265-671X DOI 10.1108/02656710810898630