Multiple sites in the western United States have produced Western Stemmed points in contexts that appear to be contemporaneous with or older than the Clovis horizon, and the geographic distribution of Western Stemmed technology in the western Great Basin, the Columbia Plateau, and surrounding regions does not show the pattern of derivation from a Clovis founding that the Clovis-first model would predict.

The most cautious interpretation of this evidence is that it complicates the Clovis-first model without definitively replacing it with an alternative.

The archaeological evidence is consistent with multiple possible scenarios: a single founding dispersal that rapidly differentiated technologically as different groups adapted to different environments; a founding dispersal that was already diverse and that distributed different technological starting points to different geographic regions; or multiple independent founding dispersals that brought different technologies from different northeastern Asian source populations.

Distinguishing among these possibilities requires evidence that goes beyond the archaeological record alone — specifically, the ancient DNA evidence that can characterize the genetic relationships among the earliest Americans and their northeastern Asian ancestors.