It's hellishly hard to get 100% on anything because of the law of diminishing returns. As you get closer and closer to 100% you get less and less back for the money and effort invested. For many large scale projects it curves off into infinity. The more complicated the project and the more variables, the harder it is to get 100%. If you have one item to deal with and one variable, its pretty easy to get 100% Deal with a million items and a thousand variables and there's virtually no chance you'll get 100%. There's not enough time or resources available in the entire world to do it! it doesn't how much you pump into the system, you'll never get to 100%

Lets take the example of lead poisoning, which is at the heart of CPSIA. Lead poisoning cases have dramatically plunged over the years due to regulations. Simply making them meant a majority of people complied voluntarily. We'll assume it follow the Pareto principle here. 80% gets done for an input of 1.

For ease of illustration we'll assume that voluntary compliance costs were $1 billion and 1 billion man hours.

Rules are tightened again. This costs twice as much to get 80% of the remaining cases taken care of. It costs $2 Billion and 2 million more man hours. You've now spent $3 Billion and 3 billion man hours to take care of 96% of the cases. Not bad!

So you do it again. You now spend $4 billion and 4 billion man hours to get 80% of the remaining taken care of. It's now a total of $7 billion, and 7 billion man hours to deal with 99.6% of cases!

And again... $8 billion, 8 billion man hours. Total $15 billion, and 15 billion man hours. You get 99.84% of cases. Hmm... not much improvement...

And again.... $16 billion, 16 billion man hours. Total $31 billion and 31 billion man hours. 99.968% Still not 100% and that was awfully expensive.

You'll never get to 100%. The problem is too big and complex to keep sticking with one single tactic and just keep devoting more money and time to it. Even unlimited resources would never take care of everything.

Lets stop at that 99.6% reduction. That's pretty damn good. Unfortunately proceeding from there gets prohibitively expensive.

But if you switch tactics, you may be able to wipe ALL the remaining cases off the board because they fall within the initial cheap 80% reduction for another tactic! For example, a lot of the gains with lead came from changing the composition of gasoline. Which would have been impossible without investing money and manpower in developing replacements for what lead did. Ditto changing the solder used in pipes.

Spend another $8 billion and 8 billion manhours on tightening regulations and enforcing lead regulations for a tiny reduction, OR spend less money and less hours working at it from a different angle that might completely take care of the remaining problem?

There's many angles to approach it from. Soil and groundwater contamination is still a major factor. Remediation of those is a good use of money. It'll also take care of OTHER contaminants in the process. Lead is still heavily used in electronics due to technical issues. Sink money into funding for next generation solder, you may wipe out the remaining cases. (and it deals with the current e-waste problem that's fueling groundwater contamination...)

Nutrition is also a major factor. Calcium, iron, and Vitamin C are key factors in the body purging lead and avoiding lead poisoning. Some studies show 90% of girls and 70% of boys in the United States are not getting enough calcium. Iron deficiency in children varies by age, but can range from 20-50% of kids. Vitamin C follows similar ranges. Imagine spending that %8 billion for reducing 0.24% of lead poisoning cases on nutrition instead... There's decent odds it may wipe ALL remaining cases... and will definitely help in other areas! Even an extra billion might achieve the same results you'd get from spending the $8 billion directly on lead reduction!


For complex systems and complex problems, taking the law of diminishing returns into account can save a lot of time and money. Two or more "good" overlapping solutions will take care of the problem more efficiently than one "perfect" solution that's unachievable due to limited resources. resources are not infinite and the sooner we realize that, the sooner we can start dealing with truly complex problems like health, environment, alternate energy, etc.