Headcount enrollment at the University of Hawaii’s flagship Manoa campus dipped below 20,000 in fall 2014 for the first time more than 10 years — and the ongoing slide is expected to continue this fall. In response, university President David Lassner is pushing for a rebound, with an aim of again hitting the 20k mark within the next three years.

Lassner, who is serving as UH-Manoa’s interim chancellor, is right to set the aggressive goal, as the campus has ample capacity to handle a significantly larger student enrollment, and almost half of its operational budget flows from tuition.

UH-Manoa must tackle retention rates and faltering graduate-student figures — about 25 percent of freshmen are not returning for a sophomore year, and graduate student enrollment plummeted by 19 percent between fall 2010 and 2016. But that’s not all. A special work group tasked with boosting enrollment also should fix its focus on Hawaii’s public schools.

This year, 10,716 high school students picked up diplomas, yet slightly less than 8 percent (848 students) are headed for UH-Manoa this fall, according to projections. Systemwide, the ranks of incoming public high school grads has slipped from 40.6 percent in fall 2011 to 34.9 percent last year.

Enrollment at nearly every campus is down — UH West Oahu and Kauai Community College are the exceptions — and the systemwide tally has dropped by 11.5 percent since it peaked five years ago with a headcount of 60,330.

Even so, the UH Institutional Research and Analysis Office, which charts projections, maintains that when placed in historical ebb-and-flow context, the 10-campus system as a whole is faring well, and that recession-fueled strong enrollment growth between fall 2008 and 2011 was an apparent anomaly.

At UH-Manoa, the baby boomers spurred enrollment to its highest-ever point (22,371) in the early 1970s. Since then it has been in slow decline, mostly.

Still, aside from the ups and downs of birth rates and the economy, there’s plenty that the university can control in its effort to add at least a few thousand students to its rolls by 2020.

Among the strategies in the works: offering attractive new degree programs, personalizing academic advising and better tracking of student trends. While tracking so far has yet to pin down why enrollment is dropping, observers point to national figures that show a gradual slip due in part to a decline in the overall college-age population, and more young adults opting to forgo college to enter a healthy job market.

University administrators and faculty must push forward with stepped-up efforts to engage would-be students; update the lineup of courses and degree programs to reflect the reality of demographics and the economy; and provide guidance and financial incentives to further boost graduation rates.

The lure of the job market — Hawaii’s unemployment is holding at 2.7 percent (the lowest rate in a decade) — underscores a need for the university to clearly communicate that investing in a college education can pay off with substantially higher earnings.

According to University of Hawaii Economic Research Organization projections, a UH graduate with an associate’s degree on average makes $360,000 more in his or her lifetime over a high school classmate who never went to college. The average UH bachelor’s degree-holder who lives and works here makes $950,000 more; and the earnings gap bumps up to $1.56 million for a postgraduate degree.

When potential career earnings are bundled with non-monetary higher ed benefits — college grads are more likely to be civically engaged and healthier than other groups — it’s clear that UH-Manoa serves a vital role in the islands.

Lassner is right to resist any impulse to shrug off the enrollment ebb. Regarding the target for 2020, he said: “That should not be unachievable. … I think there are enough things we can do in terms of students who we’re not reaching.” Agreed. UH-Manoa (and the other campuses) can do better.