Statistical specifications for highway construction provide the means to measure the important quality control attributes and ensure their compliance. The pay adjustments, part of these specifications, reflect the amount of deduction or bonus and the optimized risk distributed between the owner and the contractor. The Kansas Department of Transportation (DOT) has built a comprehensive database of as-constructed material properties for Superpave pavements from the tests required in the quality controlquality assurance (QC-QA) program. Currently, Kansas DOT pays incentives or disincentives for mixture air voids and in-place density of Superpave pavements. A practical performance model and a composite index that includes air voids, in-place density, asphalt content, and voids in mineral aggregate are needed to reflect the factors that affect the performance of Superpave pavements. The main objectives of this study were to investigate the effect of levels of significance and lot size and to develop practical performance models and a composite index for Superpave pavements in Kansas. Thirty-five projects from six administrative districts of Kansas DOT were selected in this study. Lot-by-lot comparison showed that QC-QA means were significantly different in most cases. The number of cases with a significant difference in means increased with an increase in significance level. A practical performance model and composite index from multiple quality characteristics have been proposed as an integral part of performance-related specifications (PRS) for Superpave pavements in Kansas. The performance model can be used to better understand the consequences of either exceeding or falling short of the desired quality levels and will provide a logical and defensible basis for the adjusted pay schedules that are an integral part of PRS.