Dr. David Wright, a physicist with the Union of Concerned Scientists, argues that recent intelligence estimates of a North Korean missile threat were based on exaggerated data. He points out that the missile "would be significantly different than any missile North Korea has built or tested. As a result, it is not known how long it might take North Korea to develop successfully a working missile once they started flight-testing. Moreover, official range estimates appear to assume the missile uses significantly better technology than North Korea's past missiles, including lighter materials."