Quote Originally Posted by david petley View Post
...you don't see how it is relevant?? If it is ignoring a large slice of overseas institutions, then it's findings will be insufficient to draw any conclusions that any policy, or point of debate, could be based on.

Dude, unless we know the figures for certain, it is also pure speculation on your part that they did, or would, receive a representitive number by just gathering data from a potentially small range of overseas institutions.
It is common for studies to make estimates based on smaller sample sizes. Just about every health statistics study does this, including the WHO statistics that you referred to.

That's why margin of error calculations are made, etc.

If you think that the McKinsey report doesn't use representative data, by all means, demonstrate it.