WASHINGTON (CNN) -- America's strategy in Afghanistan has been clear: Have U.S. troops step back from combat to focus on training Afghan National Security Forces so they can take over in 2014.

To hear the administration and military tell it, the plan is working.

"We're building the capacity of Afghans, partnering with communities and police and security forces, which are growing stronger," President Barack Obama said last year.

Secretary of Defense Leon Panetta said just about the same thing last month. "We have built up an Afghan army so that they are increasingly in the lead for their operations. And they are every day improving their capability."

But are the Afghans better soldiers, or is the military lowering the standards by which it measures the Afghan National Security Forces?

A new GAO report found "key definitions used in ANSF assessments have changed several times and assessments did not fully measure ANP (Afghan National Police) capability until recently."

For example, in January of 2011, the Department of Defense's highest capability rating for Afghan army units was "independent." But by August the highest rating was "independent with advisors." That meant with U.S. help, if needed.

"These changes, as well as the elimination of certain requirements for validating units, were responsible, in part, for its reported increase in April 2012 of the number of ANSF units rated at the highest level," the report stated.

The GAO also found problems with the basic reporting system for the Afghan National Army and the ANP.

"While the assessment tool did rate the ability of ANA and ANP units to meet their counterinsurgency mission, according to (the Department of Defense) it did not address civil policing and other responsibilities of the ANP," the report says.

A Pentagon spokesman said the changes were made to better assess how the Afghan forces are doing.

"The methods and tools" used by NATO's International Security Assistance Force and the NATO Training Mission in Afghanistan "have certainly evolved," Pentagon spokesman Cmdr. William Speaks said, "but the changes that have been made have been designed to more accurately track the progress of ANSF units. Standards have been made more realistic, but not less rigorous.

"Changing metrics over time is not a flaw, rather the changes represent a constant refinement and an evolution of metrics as the campaign itself progresses.