Here are some ideas policymakers have suggested to lower college costs and student loan debt.

• Debt-free or tuition-free college: Embraced by Democrats and dismissed by Republicans, the idea is to use federal and state subsidies to eliminate tuition and fees at public colleges. U.S. Sen. Bernie Sanders of Vermont introduced a bill fleshing out the idea to have the federal government pay $2 for every $1 from the state to eliminate tuition and fees. The federal funding would be paid for through a tax on transactions by some Wall Street financial firms.

• Free community college: Proposed by President Obama and now a bill before Congress known as the America’s College Promise Act, it would pay for any tuition and fees not covered by Pell Grants or state financial aid programs. Tennessee and Oregon, and some cities, have adopted programs to provide tuition-free community college.

• Reform federal student loans: There are many ideas around reforming federal student loans, including some bipartisan support for allowing students to refinance loans at a lower interest rate when possible, or barring the government from making a profit off federal student loans. Obama last year cut interest rates on some federal student loans, tied the rates to the 10-year U.S. Treasury note, created interest-rate ceilings and locked in rates for the lifetime of a loan. He also expanded a program that lets borrowers pay no more than 10 percent of their income every month for 20 years. Republicans have called for the federal government to get out of the student-loan business entirely.

• Income-share agreements: Intended to be an alternative to student loans, under an income-share agreement a private investor pays a student’s tuition in exchange for a percentage of that student’s income after graduation. Some companies already offer this agreement.

• Hold colleges accountable: Critics say some students graduate with debt and still don’t have the education or skills they need. Suggestions to make colleges have “skin in the game” range from tying state or federal funds to performance indicators or outcomes, or require colleges to pay a portion of their students’ defaulted loans.

• Increase college transparency: Thirty-two states, including Maine, allocate a portion of state higher-education funding based on performance indicators such as course completion, time to degree, transfer rates, the number of degrees awarded, or the number of low-income and minority graduates. Five more states are adopting a performance-based funding formula. Other ideas include requiring schools to track and provide post-graduation information about students, such as graduation rates, expected earnings, and loan repayment rates, so students and parents have a better sense of which programs will work for them. Indiana requires its public universities to inform students every year how much they owe in student loans.

• Tax breaks: U.S. Sen. Rand Paul of Kentucky has called for all college expenses to be tax-deductible.