In 2015 the Afghan security forces were pretty much on their own for the entire year. The soldiers, and to a lesser extent the police, were able to beat the Taliban in combat but it became apparent that the troops were better trained than many of their leaders. That was no surprise as Afghans have been fighting as tribal warriors for thousands of years. Since 2001 the U.S. has developed training programs that built on the “tribal warrior” skills to produce a disciplined (by Afghan standards) and effective (by any standard) soldier. But Afghanistan has long lacked professional officers who could employ such troops effectively on the battlefield.
Even before 2015 American advisors were telling battalion and brigade commanders that they had to outthink the Taliban develop effective countermeasures to Taliban raiding and ambush tactics. This was done but when NATO combat forces left Afghanistan in 2014 it was discovered, too late, that Western trainers underestimated the importance of Western aerial surveillance and intelligence analysis capabilities, not to mention air support with smart bomb equipped aircraft. Some of those shortages were remedied during 2015 with more such help coming in 2016. A more difficult problem was getting Afghan commanders to cut back on putting most of their troops on checkpoints and what amounts to guard duty. Instead the Americans are urging the Afghans to operate like the U.S. forces did since 2001. That means using the intel and (especially in the case of Afghan commanders) knowledge of how the enemy commanders operate to carry out attacks and raids on the enemy as soon as you locate them. That means having most of your forces trained and deployed as combat units ready to go off to raid or ambush the Taliban, especially those preparing to attack something (a town, military base or plant a lot of mines and roadside bombs along a vital road). In other words, attack the enemy before he can attack you. The Afghan troops have vehicles, radios and night vision equipment. The U.S. knows that the Afghan special operations troops can do this raiding stuff and believe that most regular Afghan troops can as well. As a result 2016 will be a different war in Afghanistan if Afghan commanders can adapt as well as their subordinates already have.