The beleaguered condition of state and local pension plans is one of those ongoing disaster stories that crops up about once a week somewhere. The explanation usually goes something like this: Irresponsible politicians and greedy public employee unions created over-generous benefit schemes, leading to pension plans which aren't "fully-funded" and eventual fiscal crisis. That in turn necessitates benefit cuts, contribution hikes, or perhaps even abolishment of the pension scheme.

But a fascinating new paper from Tom Sgouros at UC Berkeley's Haas Institute makes a compelling argument that the crisis in public pensions is to a large degree the result of terrible accounting practices. (Stay with me, this is actually interesting.) He argues that the typical debate around public pensions revolves around accounting rules which were designed for the private sector — and their specific mechanics both overstate some dangers faced by public pensions and understate others.

To understand Sgouros' argument, it's perhaps best to start with what "fully-funded" means. This originally comes from the private sector, and it means that a pension plan has piled up enough assets to pay 100 percent of its existing obligations if the underlying business vanishes tomorrow. Thus if existing pensioners are estimated to collect $100 million in benefits before they die, but the fund only has $75 million, it has an "unfunded liability" of $25 million.

This approach makes reasonably good sense for a private company, because it really might go out of business and be liquidated at any moment, necessitating the pension fund to be spun off into a separate entity to make payouts to the former employees. But the Government Accounting Standards Board (GASB), a private group that sets standards for pension accounting, has applied this same logic to public pension funds as well, decreeing that they all should be 100 percent funded.

This makes far less sense for governments, because they are virtually never liquidated. Governments can and do suffer fiscal problems or even bankruptcy on occasion. But they are not businesses — you simply can't dissolve, say, Arkansas and sell its remaining assets to creditors because it's in financial difficulties. That gives governments a permanence and therefore a stability that private companies cannot possibly have.

The GASB insists that it only wants to set standards for measuring pension fund solvency. But its analytical framework has tremendous political influence. When people see "unfunded liability," they tend to assume that this is a direct hole in the pension funding scheme that will require some combination of benefit cuts or more funding. Governments across the nation have twisted themselves into knots trying to meet the 100-percent benchmark.

While all pensions have contributions coming in from workers, the permanence of those contributions is far more secure for public pensions. Plus, those contributions can be used to pay a substantial fraction of benefits.

Indeed, one could easily run a pension scheme on a pay-as-you-go basis, without any fund at all (this used be common). That might not be a perfect setup, since it wouldn't leave much room for error, but practically speaking, public pension funds can and do cruise along indefinitely only 70 percent or so funded.

This ties into a second objection: How misleading the calculation for future pension liabilities is.

A future pension liability is determined by calculating the "present value" of all future benefit payments, with a discount rate to account for inflation and interest rates. But this single number makes no distinction between liabilities that are due tomorrow, and those that are due gradually over, say, decades.

Fundamentally, a public pension is a method by which retirees are supported by current workers and financial returns, and one of its great strengths is its long time horizon and large pool of mutual supporters. It gives great leeway to muddle through problems that only crop up very slowly over time. If huge problems really will pile up, but only over 70 years, there is no reason to lose our minds now — small changes, regularly adjusted, will do the trick.

Finally, a 100-percent funding level — the supposed best possible state for a responsible pension manager — can actually be dangerous. It means that current contributions are not very necessary to pay benefits, sorely tempting politicians to cut back contributions or increase benefits. And because asset values tend to fluctuate a lot, this can leave pension funds seriously overextended if there is a market boom — creating the appearance of full funding — followed by a collapse. Numerous state and local public pensions were devastated by just this process during the dot-com and housing bubbles.

I have skipped past several more technical objections from Sgouros (whose paper is really worth reading). But the fundamental point here is fairly simple. Accounting conventions are supposed to help people think clearly about their financial health. But in the case of public pensions, they have warned of partly imaginary danger, pushing governments to stockpile vast asset hoards that are much larger than is necessary, and created a goal which is itself rather dangerous. The next time you see someone complaining about a pension funding shortfall, check the details carefully.