Archaeologists often use measurements of standardization in ceramics as evidence for specialized craft production. Analysis of fine-ware bowl kiln wasters from the urban center of Leilan, Syria (ca. 2300 B.C.) provides a rare opportunity to test the standardization hypothesis against the archaeological record of a single production event. Scanning-electron microscopy, xeroradiography, neutron activation, and metric analyses of the wasters show extreme uniformity in manufacturing technology, chemical composition, and vessel dimensions. However, when contrasted with sherds of the same bowl type from other contexts at Leilan, a higher degree of compositional and metric variability is observed. This "cumulative blurring" effect stems from the use of long-lived types from multiple workshops. Although "cumulative blurring" increases sample variability, it does not obscure the overall homogeneity of these ceramics. Our results suggest that standardization can be a reliable index of craft specialization only under conditions of close spatial and chronological control over the archaeological record.