Two new studies suggest that college graduates entering the U.S. job market might not work in the field they studied.

They also might change jobs and careers more often than earlier generations, presenting challenges and difficulties in an economy that is experiencing disruption, experts say.

Emsi, a company specializing in labor market research, examined the job histories of about 125 million Americans. Researchers looked at the first three jobs of graduates in six fields: languages and philosophy, social sciences, business, communications, engineering, and information technology.

The study, released last month, found that many graduates started out in the field they studied in college. For example, 20 percent of engineering graduates worked in industrial or mechanical engineering in their first job.

But by their third job, many were working in an unrelated field.

Advertising, sales and financial research were among the top 10 job outcomes, or results, for all six groups. About 54 percent of all job outcomes in the study were some form of business operations.

While the study does not look at every field, the six varied fields studied had similar outcomes, suggesting career paths have changed overall.

"A lot of the way we think about work and education … is still … like, 'The jobs are scientists and writer and teacher. … What do you want to be when you grow up?' way of thinking about jobs," said Clare Coffey, a data researcher and writer for Emsi. "But the areas where there's tons of demand and tons of growth are … being able to communicate about products for companies and also oversee the process by which they're distributed."

Coffey noted that in fields like the hard sciences, such as chemistry, it is easier to communicate to potential employers what was learned in class. For students who major in philosophy, colleges and universities need to help them promote and market their valuable skills, such as written communication and forming arguments.

Edwin Koc, director of the National Association of Colleges and Employers, said his daughter, who graduated from college in 2014, has held four different jobs since then. He graduated in 1973 and has held the same number of jobs since then.

Part of the reason is a strong U.S. job market, he said. If people are unhappy, it is easier to find a better-paying job. Younger workers also have less loyalty to employers.

"They've gone through growing up during a period when their parents may have found themselves … losing their jobs or at risk of losing their jobs, during the Great Recession. And they're carrying that over with them: a skepticism about what an employer will do on their behalf," said Koc.

He suggested that employers also have power in the current labor market. As technology changes, the skills a person possesses upon graduating often become outdated within six years. And employers have more skilled workers to choose from than ever before, meaning almost anyone can be replaced.

Graduate students

This lack of straightforwardness in career paths does not just affect graduates of four-year degree programs, said Hironao Okahana, associate vice president for research and policy analysis from the Council of Graduate Schools.

Okahana and Koc agree that in the past, the job outcomes for those with a doctoral degree, or Ph.D., were much clearer. Ph.Ds require an intense level of expertise — so much expertise that most Ph.D holders once were almost guaranteed jobs as university professors or researchers.

In July, the Council of Graduate Studies released a study looking at the job outcomes for more than 4,700 Ph.D. holders. They had graduated three, eight or 15 years ago.

Few Ph.D. holders who graduated 15 years ago changed jobs recently, and most found their current jobs within three years of graduating.

This wasn't true for Ph.D. holders who graduated eight years ago, and even less likely for those who graduated in the past three years. Also, the majority of career moves for these two groups were away from higher education and into business, government and nonprofit industries.

'Education for the whole human'

Okahana said this means Ph.D. holders should not consider their first job permanent, or one in business as their last. It also means they might experience fields they never considered before. Because of this, they must try to develop as many useful skills in different fields as they can.

"Some of the … broader skills become important, which sort of points to … post-secondary education not just as a workforce development or job preparation but more … education for the whole human," he said.

Okahana, Koc and Coffey all said colleges and universities must support students in growth and change. They should urge students to take classes outside their field of study and seek out work experience in areas of interest to them. And employers should look to fill positions with individuals who might not have studied the subjects normally expected for those jobs.