One thing that stood out in Janz's paper and database was that there were very few Polynesian/Micronesian entries.
"It should be mentioned that a sample of Micronesian or Polynesian bone measurements was unavailable to test against the Nikumaroro bones. I consider it highly unlikely that inclusion of such a sample would have changed anything."
This statement needs to be put to bed. If the bones were not from Earhart, then this group would be the most likely source. This group of people needs to be more thoroughly investigated.
I'm not sure what you mean by "This statement needs to be put to bed." but I think I can explain why Jantz considers it "highly unlikely that inclusion of such a sample would have changed anything."
Let's begin by noting that Dr. Lindsay Isaac, who did an unauthorized examination of the bones when they passed through Tarawa on the way to Fiji, believed them to be the remains of an "elderly male of Polynesian race and that indications are that bones have been in sheltered position for upwards of 20 years and possibly much longer."
Hoodless, on the other hand, said, "I am not prepared to give an opinion on the race or nationality of this skeleton, except to state that it is probably not that of a pure South Sea Islander---Micronesian or Polynesian. It could be that of a short, stocky, muscular European, or even a half-caste, or person of mixed European descent."
Finally, Gallagher, who originally thought the castaway might be Amelia Earhart, changed his mind and sided with Isaac. In Fiji on July 3, 1941 he wrote, "I have read the contents of this file with great interest. It does look as if the skeleton was that of some unfortunate native castaway and the sextant box and other curious articles found nearby the remains are quite possibly a few of his precious possessions which he managed to save."
Isaac didn't explain why he thought the castaway was Polynesian. Hoodless noted that both the “orbital index” and the cephalic index of the skull indicated that the person was European. Why he threw in “or even a half-caste, or person of mixed European descent.” is a mystery. Gallagher seems to be saving face and falling in with the party line.
So why does Jantz believe that having skeletal measurements from a large Micronesian/Polynesian population would not change the statistical probability that the bones were Earhart's? Different ethnic/regional populations have different characteristic body types and proportions. You don't need a large database of skeletons to know that the Massai are built differently from Inuit. The differences can be much more subtle than that. Dr. Jantz explained to me that 20th century Europeans are typically quite different from 20th century Euro-Americans, largely due to the two wars that brought dietary/environmental hardship to European populations. Similarly, 19th century Euro-Americans are different from 20th century Euro-Ameicans due to advances in medicine and nutrition.
As Jantz shows in Fig. 3 of his paper, the humerus and tibia lengths of the Nikumaroro bones are quite different from Polynesian and Micronesian populations and most similar to Euro-Americans. Amelia Earhart, born in 1897, was a 20th century Euro-American. The 2,776 skeletons Jantz used for comparison were mostly 20th century Euro-Americans. In other words, Jantz was comparing the castaway bones to the population most likely to produce similar individuals – and yet, in that population, only 19 (.7%) of the 2,776 were more similar to Earhart than the castaway.
It is, of course, possible for a Pacific islander to be built like a 20th century Euro-American but it would be highly unusual. If we could add, say, 1,000 Microsnesian/Polynesian skeletons to the database, the likely result would be a much lower percentage of individuals more similar to the castaway than Earhart.
I, therefore, disagree with the statement that “If the bones were not from Earhart, then this group [Micronesina/Polynesian] would be the most likely source.”
(Dr. Jantz has reviewed this reply and agrees with my explanation.)