This creates a structural problem for the NAGPRA framework: the legal standard works reasonably well for remains from the past few centuries, where tribal identity and cultural continuity are historically documented.

It works much less well for remains from thousands of years ago, where the connections between ancient populations and modern tribes are real but not demonstrable in any specific way.

Various proposals have been made to address this structural problem.

Some researchers have advocated for differential standards that give ancient remains more time before repatriation, allowing extended study while still ultimately returning them.

Others have advocated for closer collaboration between scientists and tribal communities in designing research programs, so that the scientific work conducted is aligned with the questions and concerns of the communities with authority over the remains.