If meteorologists and vulcanologists developed adynamicmodel of the ash cloud's progress, it might be possible to keep more airports open, and to reroute planes to get passengers moving again.
Tax reform done right should be revenue neutral using standard CBO static analysis, but adynamicmodel would predict a large revenue windfall from the overall increase in investment and economic efficiency.
When a 20 percent soda tax is recomputed according to adynamicmodel, a 20-pound loss after five years turns into a four pound loss (assuming, that is, every other assumption in the tax model is also correct).