Gauge R&R studies that incorporate baseline information

The standard plan for gauge reproducibility and repeatability studies is for each of r operators to measure k parts n times for a total of N = krn measurements. These studies are usually planned and conducted in isolation ignoring available baseline data generated by the measurement system used for inspection or process control. This article has two goals. First, it quantifies the substantial benefits of incorporating baseline data into the analysis of measurement study data. Second, it searches for good standard plans with a fixed total number of measurements that take into account available baseline data. With operator effects being considered to be fixed, situations where the part by operator interaction is excluded from or included in the model are investigated. The analysis of the combined data is based on maximum likelihood estimation and the ranking of plans on the approximate standard errors of the estimates using the Fisher information matrix. The benefit of incorporating baseline data into the analysis is significant and most of the gains in precision can be obtained with small baseline sample sizes. In general, depending on the context and number of baseline measurements, the standard plan with either the minimum or maximum number of parts is recommended.