[bumby]

What would you propose as a better metric of innovation?

I don't think there's a single perfect measure but if you put it in broader context of measures like Nobel prizes R&D spending, patents, etc. it does seem to paint the picture that the US disproportionately contributes to medical innovation.

It's very similar to the measure of health. There is no single great metric. Using a single metric like BMI or blood pressure is flawed. However, you can get a clearer picture if you bring together multiple metrics.