As college students dig into their studies this fall semester, they may want to look up from their textbooks to consider whether their education will provide a solid bang for their buck.

Not all college majors are created equal when it comes to lifetime earnings, according to a recent study from The Hamilton Project, an economic policy think-tank that's part of the Brookings Institution. Four degree majors will see median lifetime earnings of more than $2 million, while some grads with lower-earning degrees will earn less than half of that, the study found.

Across the board, a college education is worth the investment, with the organization finding that median earnings of bachelor's degree graduates -- for all 80 majors -- paced ahead of earnings for high school grads.

Get Breaking News Delivered to Your Inbox

But to hit upon the sweet-spot of maximum lifetime earnings, college students should consider fields with quantitative skills, such as engineering and operations and logistics. Which majors are at the bottom? Those associated with careers working with children -- elementary eduction, for example -- and counseling, such as social work.

The findings should provide "a springboard for discussion regarding educational investments, financial aid, career choices and social opportunity," researchers Brad Hershbein and Melissa Kearney write.

Four majors provide median lifetime earnings of more than $2 million, according to the study: chemical engineering, aerospace engineering, energy and extraction engineering, and computer engineering.

The degree that holds the least value as measured by lifetime earnings is early childhood education, where graduates will bring home a median of about $800,000 over the course of their career, The Hamilton Project found. The next three lowest-earning majors are family and consumer sciences; theology and religious vocations; and fine and studio arts.

Engineering degrees offer the highest median lifetime earnings for among college majors (ranking index in millions of dollars). The Hamilton Project

Of course, students aren't driven by earnings potential alone, and the study cautions that families and their children should consider several nuances. For instance, a student with a passion for psychology -- which is ranked in the bottom 20 of the lowest-earning majors -- may not find enjoyment or have the skills to succeed in civil engineering, the seventh highest-earning major.

"Future earnings are not the only factor in choosing a major: personal enjoyment, engaging in meaningful work, and filling a social need should all also enter into a student's decision-making," the report notes.

College majors also have a huge variation of earnings for individual graduates, the study found.

"Cumulative earnings double -- or even triple -- when moving from the bottom quarter to the top quarter of earners in a given major. These increases are larger for lower-earning majors," the researchers note.

Take students who study music. While that degree is ranked as the eighth-lowest-earning major, with median lifetime earnings of less than $1 million, top-earning musicians can pull in solid six-figure annual incomes. Musicians in the New York Philharmonic, one of the country's top orchestras, earn a base salary of about $138,000.

Regardless of a student's chosen major, getting a college degree is a savvy financial decision, given the typical college graduate will earn $1.19 million in today's dollars, the study found. That's double the lifetime earnings of a typical high school graduate, at $580,000.

The total cost of earning a degree is about $102,000 on average. That means that even if the cost is subtracted from the lifetime earnings of every college major, earning a degree still helps students come out ahead of high school grads, the think-tank notes.

The researchers say, "The good news is that no matter what their major, they are likely to earn more over their careers than those with less education."