Empirical evidence that IP is a good thing?

Techdirt: "Intellectual property laws are created without any empirical evidence that they are necessary or that they will help rather than hurt." This is the argument we've been making for years. For us, the question of intellectual property isn't a "moral" issue. It's not about how "information needs to be free." It's an economic issue, plain and simple. There's increasing evidence to show that many of these intellectual property laws tend to harm innovation and slow down economic development. It would seem like these are the types of things that anyone making intellectual property laws would want to understand. Instead, they seem to insist that "more protection is better" when the evidence has shown the opposite to be true.

The evidence for this was a 2002 post on Techdirt:
A new report from the Commission on Intellectual Property Rights goes even further in their description of the dangers of current intellectual property laws. They point out that, in many cases, intellectual property laws are very bad for the poor, and delays the growth of new ideas and technology. The report recommends that many developing nations not set up a similar draconian intellectual property system. I have to say I'm surprised, but glad, to see that this topic is receiving some serious debate. Too many people seem to assume that current intellectual property laws must make sense. There are better ways to support intellectual property without resorting to laws that actually hold back innovation.

Saying the IP laws delay growth of technology, proving it is another. Pharmaceutical research is an example wherein IP laws have stimulated research and created new drugs. Even with strong funding by the NIH and others, it still takes the "promise of return" to pay for the development and testing.