In the last year, the number employed has gone up 1.8 million but the number in the labor force has gone up only 1.1 million. Because the number employed has gone up faster than the number in the labor force, the unemployment rate has dropped (from 4.7% to 4.3%).
Since 1983, the unemployment rate has been lower than its current 4.3% just 5% of the time - and all of that between 1999 and 2001. Outside of that period, it's never been lower than it is now.
So what does that mean when it comes to forecasting job growth? It means that at some point between now and the end of 2018, the unemployment rate will be as low as it can go. At that point the rate of job growth will be limited by the rate of labor force growth.
Labor force growth in the last year has been nearly 100,000 a month. (And shrank by more than 400,000 people in May as baby boomers retired and fewer Americans looked for work.) During the recovery from 2011 to 2016, job growth averaged 203,000. That gap is not sustainable at full employment.
This makes a couple of things predictable for the Trump term.
1. Job growth in the first four years of Trump's administration will be about half what it was in the last four years of Obama's administration. (Closer to 100,000 jobs a month than 214,000).
2. We will have our first month of negative job growth within the next 18 months. (Simply put, given normal variation, a median value of 100k is far more vulnerable to slipping below zero than is a median value of 200k. For instance, in March the economy created only 50,000 jobs.)
There are other factors.
On a positive note, the labor force participation rate could rise, prolonging the time when job growth exceeds labor force growth.
On a negative note, Trump's policies will discourage immigration of all kinds. Tourism has already dropped. Universities are reporting fewer applicants from abroad. This sort of things takes time to show up in numbers but as foreigners are less willing to live in an xenophobic America, we lose twice. Once because those immigrants don't come here to join our workforce and a second time because as they choose to live and work in places like Eindhoven, Netherlands or Vancouver, British Columbia, they create more jobs in those communities rather than ours. An Iranian who works on robotic sensors will help to make a team successful in some other country and all of the jobs that ripple out from that effort - the project managers and administrators within his company or the restaurateur or furniture salesperson outside of his company - will be in a different country as well.
Pew forecasts 18 million fewer potential workers without immigration. In such a scenario, the number employed would shrink for decades, shrinking the economy with it.
You might easily dismiss this prospect of a sharp decline in immigration as unthinkable. Of course just a year ago, the thought that Republicans would be arguing that we should ally with Russia rather than NATO would have been unthinkable, as would have cuts of 21% to National Health Institute (NIH) or slashing Medicare by half. Trump is disruptive and prides himself on that. It would be silly to bet on him reversing his position on immigration.
Three other huge variables are trade deals, climate change technology, and cuts to science funding. If Trump slaps tariffs onto trading partners and sets off a trade war, our economy will slump. If his policies continue to focus on protecting coal mining jobs that originated in 1740 rather than creating new technologies and jobs in alternative energy, our economy will fail to thrive. If he slashes funding for science and research (like his proposed 21% cut to NIH), he will undermine the creation of new products and technologies that would create jobs in two to twenty years.
Job growth will be less vibrant under Trump. (And to be fair, it would have been with anyone, from Sanders to Clinton to Bush to Trump.) If he gets his way with policy proposals on immigration, trade, and defunding the development of alternative energy and other technologies (new medicines that could have emerged from NIH research, for instance), we will be measuring the net loss of jobs each year, not their creation, tracking a steady decline of 100,000 jobs each month rather than bemoaning a gain of only 200,000 a month as anemic.