The State-Trait Anger Expression Inventory (STAXI, Spielburger, 1996) and its recently revised edition, the State-Trait Anger Expression Inventory, 2nd Edition (STAXI-2; Spielburger, 1999) are well-known instruments for assessing anger. In contrast to the Beck scales and the Qpass scales, which assess negative emotions over a 1-2 week time span, the STAXI measures a negative emotion, anger, as both as an enduring personality “trait” and as a temporary “state” experienced at the time of testing.

The STAXI consists of 44 items that form six scales: State Anger, Trait Anger, Anger-In, Anger-Out, Anger Control, and Anger Expression. In responding to each of the STAXI 44 items, individuals rate themselves on 4-point scales that assess either the intensity of their angry feelings or the frequency that anger is experienced, expressed, suppressed, or controlled. The STAXI-2, a revised and expanded version of the STAXI, consists of 57 items that form the same six scales on the STAXI. An Anger Expression Index has been added that provides a general index of anger expression.

Sensitivity to treatment changes. While the STAXI and STAXI-2 assess anger as both a long-standing trait and as a transient state at the moment of testing, Qpass’s Anger-Scan scale assesses the severity of anger over the time span of a given week. Hence, Qpass’s Anger-Scan may be more sensitive to treatment-induced changes, especially in mental health settings where patients are typically seen on a week-by-week basis.

Items. Some items on the STAXI and STAXI-2 use metaphorical and vernacular language. Examples include “I have a fiery temper,” “I am a hotheaded person,” “I boil inside,” and “I fly off the handle.” In contrast, Anger-Scan was developed in strict adherence to modern test development standards that discourage the use of metaphorical terms that can be considered dated in later years or that may have culturally based meaning. Comrey (1988) recommends that test items be free of "slang, trendy expressions [and] potentially dated material” (p. 757). As Comrey (1988) states, “The language should be such that it will be as suitable 10 - 20 years from now as it is today" (p. 757).