The Wheeler-Kenyon system involves digging within a series of 5x5 meter squares set within a larger grid. This leaves a (1 meter wide) freestanding wall of earth--known as a "balk"--on each side of a unit. These vertical slices of earth allow archaeologists to compare the exact provenance of a found object or feature to adjacent layers of earth ("strata"). During Kenyon's excavations at Jericho, this technique helped discern the long and complicated occupational history of the site. It was believed that this approach allowed more precise stratigraphic observations than earlier "horizontal exposure" techniques which relied on architectural and ceramic analysis.
There are several problems associated with the Wheeler-Kenyon Method. First, this stratigraphic dating technique can only be applied to a site that has formed in identifiable layers; this criterion excludes many sites in North America. It also cannot be used on large-scale projects, and leaves no opportunity for re-excavation by future archaeologists using improved techniques.