Stretcher (furniture) Stretcher (furniture) A stretcher is a horizontal support element of a table, chair or other item of furniture; this structure is normally made of exposed wood and ties vertical elements of the piece together. There are numerous styles of the stretcher including circumferential, double and spindle design. This term is sometimes referred to as a stretcher beam. A very common pattern for chairs has each front leg connected to the back by the lateral stretchers, which in turn are connected by a medial stretcher. In the William and Mary period chi (from the Greek letter chi - Χ) stretchers were
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