The act is also beneficial because it has created greater dialogue between Native American groups and museums, Flynn said.
"The legislation has promoted interactions between museums and tribes on a faster track than had been going prior to the legislation so the net result is more interaction and new interaction with the still evolving culture of native peoples," Flynn said.
"The act is facilitating a real dialogue that a lot of museums hadn't been involved in before," said Stern, the Berkeley NAGPRA coordinator.
But Pilbeam was not concerned with the overall impact of the act.
"At the moment, my own personal opinion is that with the exception of human remains, far fewer objects will be returned than originally thought."
He said he believed based on his observations that many tribes have quite narrow definitions of the relevant categories of objects.
"While we might consider a set of objects sacred and include those in a list we send to the tribe, the tribe might view only a few as being sacred from their perspective," Pilbeam said. "But they might also decide that an object is sacred that we might not have included on the list and that comes out on a visit. It seems at the moment that fewer objects are affected than anticipated."
Pilbeam said there were instances where a tribe had agreed to leave an object with the museum rather than repatriate it.
According to Isaac, the Zuni decided to leave some human remains with the Peabody Museum because burial is by clan and each clan has different customs. Since the specific clan could not be identified from the remains, the Zuni decided not to repatriate those remains.
Disputes
Some have said the lack of clarity in the law may lead to disputes over what artifacts need to be repatriated.
Ayau said his group had a dispute with the Hearst Museum at the University of California at Berkeley.
"The Federal Repatriatism Process requires an identification of the human remains. The Hearst Museum did not believe the two sets of remains were native Hawalian and therefore refused to return them," the said.
"Our group raised this dispute with the Review Committee stating that the evidence established the remains were Native Hawailan," Ayau said. "The committee ruled in our favor and the remains were reburied."
Pilbeam said that the Peabody Museum had not had any disputes.
Isaac said the tribes must demonstrate right of possession.
"You can't make a claim for something that is not yours," she said.
"Somebody shouldn't think that because they're an eighth Navajo that they can back up a truck to a museum that happens to have Navajo artifacts," Stern said.