Really, there's a ton of information out there about this. And it is fairly easy to access it. It is collected and reported and interpreted by the Department of Labor in your state as well as at the federal level. Your state will have some sort of labor market/career center/job seeker offices in each city or local area. These centers are located usually with state unemployment offices or as part of helping agencies, though they are not services for the low income exclusively. Any vocational training/career training that is affiliated with the state, non private schools, are monitored and are usually discouraged from even offering courses for which there is not a good chance of jobs being available in the field.
They have counselors at Career Centers who can show you how to access all the labor market information,how to interpret it, tell you where appropriate training may be available. High school guidance counselors also have some training at giving job selection advice.
But one place you are NOT going to get a realistic picture of what the employment picture is for the type of education they're wanting to provide is from the school itself. particularly the private schools, where they can offer to train you up as a dog groomer or a make up specialist, and generally assure you that 95 % of their graduates are currently employed. (At something.....they don't mention what) All they're really interested in is that PELL grant or loan that you took out and the money you'll be paying them upfront. These things are not being too carefully monitored lately, after all, we have some pretty prominent persons right now who thought this was a great way to make money a few years back!