Topeka ? A decades-old Kansas policy that keeps secret the names of those who receive millions of dollars in tax credits is designed to protect taxpayer privacy, state officials said, but some lawmakers argue it keeps them from knowing which breaks are worth keeping.

The Kansas Department of Revenue’s yearly report on tax expenditures shows the state spent at least $622 million in 2013 on income and privilege tax credits that allow qualifying taxpayers to subtract the amount of taxes they owe for a wide range of reasons. That dollar figure is incomplete, though, because it doesn’t include information on 31 credits listed as confidential, The Wichita Eagle reported.

State law doesn’t specifically bar the revenue department from releasing those numbers, but forbids it from releasing individual taxpayers’ information. Revenue officials have interpreted that as preventing the release of the numbers when there are fewer than five beneficiaries.

“The rationale is that by law, taxpayer data is confidential. . When we are dealing with taxpayer data for 5 or fewer taxpayers, there is a risk that disclosure of this data may in fact reveal confidential data concerning one or more taxpayers within that group,” agency spokeswoman Jeannine Koranda said in an email.

Even disclosing the aggregate total for the 31 different credits listed as confidential would violate the agency’s policy, she said.

In Missouri, where information about tax credits — including the identities of those who receive them — is easily found on a state website, there is no evidence that revealing that has had any impact on the business climate, said Greg LeRoy, executive of Good Jobs First, which advocates for accountability with tax incentives.

Missouri created an online database in 2007 known as the Missouri Accountability Portal. Department of Revenue spokeswoman Michelle Gleba said the agency has made it a priority to put as much information online for taxpayers as possible.

Kansas Senate Vice President Jeff King, an Independence Republican, said keeping the cost of tax credits confidential, even from lawmakers, impedes policymakers from making decisions. “It’s very hard to do that effectively if there are certain tax credits we don’t even know what we’re spending on,” King said.

Jeff Melcher, a Leawood Republican, said he can’t think of a good reason for keeping the names of beneficiaries of tax credits confidential, “other than other people would be complaining that they’re not getting it . which I don’t think would be a particularly compelling argument.”

As for recipients who don’t want the information disclosed, Melcher said “don’t take the money.”