A majority of more than 1,000 college and university presidents surveyed in a new poll said that public high school students are arriving at college less well prepared than students were a decade ago, and only 19 percent said that the U.S. system of higher education is the best in the world today.

The report, called “ Is College Worth It ?” and issued by the nonprofit Washington-based Pew Research Center, also said that three-quarters of American adults say college is too expensive for most Americans to afford, and 57 percent said the higher education system does not provide students good value for the cost. Still, 86 percent of college graduates agreed that attending college had proven to be a good personal investment, it said.

The report was based on two surveys, one conducted on the phone with 2,142 people who were 18 years and older and another conducted online, in association with the Chronicle of Higher Education, among presidents of 1,055 presidents of institutions of higher education. Those schools include two- and four-year private, public and for-profit.

Among the findings of the phone survey:

*Graduates of four-year colleges believe on average they earn $20,000 more a year than they would without the degree, while adults who don’t have one believe that they are earning $20,000 less than if they did. The U.S. Census Bureau in 2010 reported that the median gap in annual earnings between a college graduate and a high school graduate was $19,550.

*Though 94 percent of parents surveyed said they expect their child to attend college, most young adults can’t attend a four-year school because it is too costly.

*The public has mixed views of the mission of a college education. Forty-seven percent say the main purpose is to teach skills that will prepare a graduate to get a job, while 39 percent view college as a time to grow personally and intellectually. The rest saw both missions as equally important.

Here are some of the results of the online survey of college and university presidents:

*Sixty percent of the presidents said they believe the U.S. higher education system is headed in the right direction, but only 19 percent say it is now the world’s best. Fifty-one percent of the presidents described the U.S. system as one of the world’s best.

Answers to this question were different based on the selectivity of the school. Those who said the U.S. higher education system is the best in the world were:

— 40 percent of presidents of highly selective colleges and universities

— 22 percent of heads of schools with medium selectivity

— 14 percent of presidents of schools with lower selectivity

*Fifty-eight percent of the college presidents said that high school students are coming to college less prepared than kids were 10 years ago, and 52 percent said college students don’t study today as much as their counterparts did a decade ago.

*Twenty-seven percent said that faculty at their own schools are too lenient in grading students; 73 percent said grades are about right.

*Sixty-four percent say it is not likely that the United States will achieve the goal set by President Obama to have, by 2020, the world’s highest percentage of college graduates.

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