The goal is to maximize reachability while minimizing stress at each joint.
To do this, researchers determine the area of reach (boundary envelope) and move the work space to optimize these cost functions (Abdel-Malek, Yang, 2004). Imagine a coordinate system originating at each joint and motion constraints depending on the magnitude and range of the vectors (limb portions).
Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).
Additional complications come from the burning of fossil fuels such as coal and oil, and from the above-ground nuclear tests done in the 1950s and 1960s.
It is an absolute dating method, and does not depend on comparison with similar objects (as does obsidian hydration dating, for example).