KABUL, Afghanistan — American officials, when looking to quickly illustrate progress in Afghanistan, have in the past few months highlighted a 7 percent drop last year in what they call “enemy-initiated attacks.” Fewer attacks, the reasoning went, meant Afghans were safer and the Taliban were weaker.

The problem: There was no decline. The numbers were wrong.

The American-led NATO coalition said Tuesday that it had discovered a clerical error in its reporting and that the number of enemy-initiated attacks — defined as attacks with guns, mortars, rockets or improvised explosive devices — remained constant from 2011 to 2012.

Though the mistake may be embarrassing, it is not likely to greatly change perspectives about how the war is going. That is in part because, outside of official circles, few analysts have seen the violence statistic as good news.

In fact, the same measure, when looked at over a wider sample of years, actually depicts a drastic growth in violence since 2009, when American commanders first began inching toward a counterinsurgency strategy that focused on reducing violence rather than solely on battling militants.