Spatially delimited "sites" were deprioritized in this project in an effort to capture changes in the continuous field of obsidian artifacts and related sites as one approaches the obsidian quarry workshop area. Rather than relying on the ill-defined concept of siteas the basic unit of analysis (Dunnell 1992), the Upper Colca Project survey team focused on recording lociof different artifact classes. Site boundaries were in fact recorded, however, because it was impractical to record isolates in the same detail as one recorded spatial structure in the concentrations conventionally thought of as a site.

For example, it was difficult to reconcile the density of the category High density lithic scatterbetween a workshop at the obsidian quarry, on one hand, and a residential base in the valley bottom; a problem that was resolved with sampling. Furthermore, pottery was almost non-existent in the lithic quarry area, even though on a regional scale there is ample evidence of consumption of obsidian by groups that possessed ceramic technology. In order to examine data in an integrated framework, broad categories such as "Site Type" were given minimal priority in favor of explicit and comparable categories based on features and on artifact concentrations described as loci. Broad site typecategories were assessed primarily for purposes of cartographic representation and to facilitate communication in the course of research, however analysis and interpretation focused on basic and comparable categories of data by artifact class.