A billion dollars is big money in anyone’s book. Especially when those dollars come from you, the taxpayer. That’s how much money the US Railroad Retirement Board says might have been scammed by Long Island Rail Road retirees falsely claiming disability benefits.

The scandal began unraveling five years ago when it came to light that nearly all LIRR workers retired early with both a Metropolitan Transportation Authority pension and a federal disability benefit.

It then emerged from the Government Accountability Office that LIRR employees apply for disability claims at 12 times the rate of workers in equivalent commuter railroads across the country. Nearly 80% of those claims are approved.

David McGlynn

Dr. Peter Ajemian

Between October 2011 and May 2012, the US attorney for the Southern District indicted two dozen people for fraud, including a former conductors-union president and two orthopedists. The scheme involved workers filing — and the doctors approving — fake disability claims.

One doctor, Peter Ajemian, approved 94% of the disability claims before him over a decade. He pleaded guilty in January and admitted that nearly all the patients he declared disabled were, in fact, not. And his guilty plea launched the Railroad Retirement Board’s review of all disability claims.

We’re glad to see the investigation. But it’s taken four months to come to a decision — following three urgent requests from its inspector general, who explained that paying out arguably fraudulent claims was costing the board $2 million per month.

As valuable as official investigations are, the primary vehicle for accountability in a democracy is the citizenry itself. Whether your tax dollars are funding a retired teacher or a street repair, you deserve to know how your money is being spent.

That’s the aim of litigation by the Albany-based Empire Center, which has been seeking information about who gets how much from the government in the form of pensions. The center runs an excellent page called SeeThroughNY.com, where you can find all sorts of information about how your money is being spent.

This fall, New York’s highest court will take up an Empire State initiative to gain the names and pension amounts for retired teachers. If successful, that would likely mean that similar information for other pension funds for city and state government workers would also have to be made public.

Transparency won’t solve every problem. But taxpayers will never ensure their dollars are being spent wisely and honestly until they know exactly where those dollars are going.