Skillet (band) nominated and won a Dove Award for Rock Song of the Year for their song "Sick of It". "Vital Signs", a compilation album released exclusively in Europe, was released October 13, 2014. On February 16, 2015 Skillet announced they were writing material for a new album with recording to begin in June with a potential release in the late half of 2015 or early 2016. On April 8, Skillet released a preview of a new song, later revealed to be called "Out of Hell", on their social media pages. On May 20, 2016 the album's title, "Unleashed", was announced and
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