WASHINGTON — Six federal agencies may want to hide their report cards after a non-profit group doled out failing grades Tuesday for bad grammatical behavior. A 2010 law requires bureaucrats to write official documents with the public in mind — less jargon, more verbs — but some writings remain more incomprehensible than others.

Under the statute, agencies must provide information on programs, services and taxes in clear sentences. For example, “addressees” can be just “you.” Active voice is in, and double negatives are out.

Agencies “need to write for their intended audience, and it’s not for lawyers. It’s for taxpayers filling out forms, and farmers trying to get government loans, and people applying for HUD loans,” said the law’s author, Rep. Bruce Braley, D-Iowa. “Until every grade is an A, we will keep holding these bureaucrats’ feet to the fire.”

A non-profit group called the Center for Plain Language judged agencies on two standards — compliance with the law and use of plain language in current documents. The center measures clarity through sentence length, percentage of passive voice and use of personal pronouns.

One complaint is clarity. An example comes from the Department of Transportation’s Airworthiness Directives: “No person may operate a product to which an airworthiness directive applies except in accordance with the requirements of that airworthiness directive.”

Translation? “FAA’s airworthiness directives are legally enforceable rules that apply to the following products: aircraft, aircraft engines, propellers, and appliances.”

The 20 reviewed agencies got mixed results. Annetta Cheek, chairwoman of the Center for Plain Language, said the departments of Justice and the Treasury were “major disappointments,” given they work so closely with citizens. Justice got two D’s, and Treasury got a D for plain writing and an F for compliance with the law.

The departments of Housing and Urban Development, Homeland Security and Labor, the Environmental Protection Agency and NASA also received failing grades. But the winner is the Social Security Administration, which got straight A’s, a jump from its mediocre 2012 results.

Major agencies, such as the State Department and Education Department, were left off the list because the group does not “have the resources to do everybody,” Cheek said. “Next year, we’ll drop the ones that do best and pick up others.”

The law has no penalties for non-compliant agencies, but Rep. Braley said keeping track of the agencies’ progress — or lack thereof — “will give more incentive to go back and put more teeth in the law” for stronger use of plain language.