Skillet (band) international tour in January and February 2011 visiting Australia, New Zealand's Parachute Music Festival, and Japan. In October 2011, the band continued their "Awake and Alive" tour with Disciple, We as Human, and Manafest. Skillet headlined the Winter Jam Tour 2012 for the central and eastern parts of the United States. Starting on August 13, 2013, Skillet toured with Shinedown, Papa Roach, and In This Moment on the Carnival of Madness Tour. In October and November, the band arrives Europe supporting Nickelback's tour in twenty one shows. The band closed the year headlining their own tour in Russia and a
Differential item functioning Differential item functioning Differential item functioning (DIF) is a statistical characteristic of an item that shows the extent to which the item might be measuring different abilities for members of separate subgroups. Average item scores for subgroups having the same overall score on the test are compared to determine whether the item is measuring in essentially the same way for all subgroups. The presence of DIF requires review and judgment, and it does not necessarily indicate the presence of bias. DIF analysis provides an indication of unexpected behavior of items on a test. An item does not display DIF if