Time-sensitive projectile point distributions from survey can be used to produce "calibrated counts" for sites in a given region as has been applied in studies in the Titicaca Basin (Craig 2005:453-468;Klink 2005;Tripcevich 2001) and in other regions. Calibrated counts are valuable measures because time periods assigned to projectile point styles are of different durations, and thus direct comparisons between site counts for a given time period can be misleading. For example, the Middle Archaic is 2000 years in length while the Terminal Archaic is only 1300 years in length, therefore there were more years by a factor of 1.53 for sites to occur in a given time period.
However, in the Upper Colca study, site counts were not systematically calibrated for two reasons. First, as mentioned above, there were virtually no single-component sites identified in this survey. Due to the aggregation of settlement around water sources and sheltered places in the higher altitude portion of the survey, virtually all sites with more than two diagnostic artifacts were shown to be multicomponent sites. Second, this research was conducted in the vicinity of an obsidian source and the evidence from this study and work elsewhere in the region show that obsidian is strongly correlated with Series 5 projectile points belonging to the later Prehispanic time periods. Therefore projectile point style and length of time are not independent variables such that one could be used to calibrate the other, because obsidian was increasingly in demand and further circulated during the Series 5 time period.