During a recent meeting at the Federal Reserve Bank of New York, William Dudley, the bank’s president, noted that “there are many important questions still left unanswered” about student loans, adding, “but it is very hard to answer these questions with existing data.”

Why can’t we answer these basic questions about student debt? The Education Department runs the federal loan program, but it has not released detailed analyses or handed the data to those who could do the necessary number-crunching.

The Federal Reserve, which tries to keep a close eye on household debt, has purchased credit records from Equifax that let it track trends in student debt. That’s right: The central bank relies on a private firm for data about student loans, when much of the data it needs is held by a federal agency. The credit records are better than nothing, but they lack crucial details like the type of loan and the college the borrower attended.

Of course, the Education Department publishes some information about its $1 trillion student loan portfolio. Several spreadsheets sit on a department website, and that is where Denise Horn, a department spokeswoman, directed me when I asked about the loans.

But this data doesn’t say much. It does not provide delinquency rates for all loans, for example, or information about how many borrowers have managed to renew their debt relief. To get such additional information, Ms. Horn suggested, a Freedom of Information Act request would be appropriate.

David A. Bergeron spent 34 years at the Education Department, ending up as an assistant secretary for postsecondary education. He left in 2013 and is now vice president for postsecondary education at the Center for American Progress, a Washington research organization. Mr. Bergeron says he is frustrated by the incomplete data. “The department releases only very high-level summary statistics, which do not allow us to understand the problems facing individual student borrowers,” he said. “Trying to solve a problem with incomplete information leads you to the wrong solutions.”

By contrast, we know far more about the mortgage market. The consumer bureau, along with other agencies, publishes extensive, detailed information about mortgages, lenders and borrowers. Government and private analysts use this information to gauge, in real time, the mortgage market’s health. Along with the Federal Housing Finance Agency, the consumer bureau is taking this already detailed data further, creating a national database that will track home loans from origination through payment.