We're all familiar with the Bureau of Labor Statistics numbers on job growth in the planning field. US News bases their reports on these numbers, as well as nearly all other sources on job prospects. In other words, this is the strongest, most authoritative information we have on how many jobs there might be for planners in the future.
A while ago, after doing some brief research on how these numbers are derived, I posted about how these statistics are basically a combination of historic growth with vague, anonymous tweaks by BLS economists, most likely just adjustments based on overall economic downturn. Most of the BLS data is qualitative, as they talk about how more people are moving to cities, and therefore there will be an increased need for planners, etc. Rather than debate these assumptions, this post assumes that the BLS data is relatively correct in predicting future planning employment.