Skillet (band) program on a summer missions trip with teenagers to Mexico. In 2008, they joined Teen Mania Ministries and toured with Acquire the Fire. Skillet joined Breaking Benjamin, Three Days Grace, and Seether on the first half of their tour in fall 2007. Then Skillet headlined their own "Comatose" Tour alongside Thousand Foot Krutch and traveled to approximately 30 cities. The tour started on March 28 and ran through May 11, 2008. Skillet toured again from April 2009 through June 2009 with Decyfer Down and Disciple. This tour was called Comatose Tour 2009 (essentially a second branch of the 2008 Comatose
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