As an economist, I think of the incentives at work in a complex situation and try to derive better solutions (not that they always are better...) Anyway, I've thought about the PED use problem, and have several thoughts on what might work better to reduce the incentives to use PEDs:
The IAAF and USATF are non-governmental organizations; they are essentially voluntary membership associations. The WADA is an umbrella organization of these voluntary associations. The penalties they impose are akin to civil lawsuits operating under their own rules, not governments imposing criminal penalties. As such, they are not constrained by government constitutions to rules of evidence or scope of penalties in the same manner. Essentially they can write their own rules so long as they are reasonable and don't violate basic human rights guaranteed in a local government constitution, e.g. non-discrimination. Given this, I suggest the following enforcement policies.
Many of the athletes "caught" seem to be late in their careers (e.g. Jacobs, Mitchell, Decker). The incentives are obvious at that point: not caught--potentially additional victories and income; caught--premature retirement on a career already about to end. In other words, they have lots of upside potential with little to lose. The appropriate solution seems to be to make the downside at least as large as the upside, particularly on a probability weighted basis. The following actions should be taken to create that type of environment:
1) Remove the athlete's results and awards from ALL previous IAAF-sponsored competitions. This would include the return of all monetary prizes. (This may require civil actions through the courts.)
Two issues here: I don't know how the NCAA will respond to this. And more importantly, it may require a contract between all athletes and the IAAF worldwide that sets the start date for the retroactive "death" penalty to the beginning of the policy. Nevertheless the policy will have almost universal coverage of all meaningful competitions and competitors within a decade given the length of careers.
2) Require IAAF-affiliated sponsors to include their contracts a clause that an athlete will repay some portion or all of their sponsorship fee if they fail a drug test or a certain number and type of drug tests. In addition, perhaps the athlete might be required to repay some portion of the product investment that a company made specifically with that athlete in mind (think of "Air Jordans").
I don't know the actual relationship between the IAAF/USATF and major sponsors e.g., Nike. The IAAF may not have the lines of authority to impose this requirement. On the other hand, it might be able to persuade key sponsors to include this clause in future contracts.