Greenspun's arguments are bit a flippant, as noted here in the ending comments:<p>"To see just how much of a factor this is, look at how mishap rates plummeted after the introduction of CRM training at US carriers in the late 1970s/early 1980s. Prior to widespread CRM training, the culture at major US carriers was largely as Gladwell describes current foreign carrier culture: the captain's word was final, and co-pilots didn't speak up or contradict the captain."<p>Dismissing PDI out of hand as "already handled" is perhaps being disingenuous about the role it may play.