PayScale was able to collect data on colleges based on the following major groupings:
Humanities Majors: English language and literature, philosophy, foreign languages, history, minority studies, etc.
Engineering Majors: Mechanical engineering, electrical engineering, chemical engineering, petroleum engineering, civil engineering, etc.
Art Majors: Drama, music, industrial design, graphic design, fine arts, etc.
Business Majors: Business, marketing, finance, accounting, etc.
Computer Science Majors: Computer science, computer engineering, as well as math, statistics, etc.
Economics Majors: Economics, micro-economics, macro-economics
Science Majors: Biology, chemistry, geology, archaeology, microbiology, etc.
Psychology: Comparative Psychology, Social Psychology, Clinical Psychology, Forensic Psychology, etc.
PayScale only includes those schools for which we have enough data from alumni with that major on each College ROI Report by major list. This means that our lists are not comprehensive - schools not listed on each major ranking may offer that major, but we were not able to collect a statistically significant data pool to include it. Our breakdowns of college return on investment by major can help you get an idea of how alumni who earned a bachelor's degree only in the specific major you are interested in fare at different schools. For example, if you really want to major in art history, start by considering those schools where we know that humanities majors go on to earn a decent ROI, because it means that those alumni find jobs that pay well. Knowing how much alumni with your desired major earn over 20 years will also help you figure out how much you can afford to pay for college, or take out in loans. Going into debt for an engineering degree isn't a bad idea, since most engineering grads see high ROIs. However, if you are considering a degree in the arts, you might want to be conservative with how much debt you take on, since the resulting ROIs for art majors are much lower overall.
There are not good majors or bad majors. STEM (science, technology, engineering and math) majors do tend to earn more, but there are plenty of schools with high ROIs for alumni who study the humanities and art. You just have to make a smart investment, and thinking about college in terms of cost and future earning potential is a good step in that direction.