State-Trait Anxiety Inventory
The State-Trait Anxiety Inventory (STAI) is an introspective psychological inventory consisting of 40 self-report items pertaining to anxiety affect. The STAI was constructed by Charles Spielberger, R.L. Gorsuch, and R.E. Lushene, based on the state-trait distinction proposed by Raymond Cattell in 1961. Their goal was to compile a set of items that could measure anxiety at both poles of the normal affect curve (state vs. trait). Feelings of unease, worry, tension, and stress can be defined as anxiety. Feelings of anxiety may occur in stressful situations such as when confronted with an important test or interview, or may be associated with psychological disorders such as obsessive compulsive disorder or generalized anxiety disorder. The STAI purports to measure one's conscious awareness at two extremes of anxiety affect, labeled state anxiety (A-state), and trait anxiety (A-trait), respectively. Affectivity ranges from immediate, transitory emotional states, through longer-lasting mood states, through dynamic motivational traits, ranging all the way up to relatively enduring personality traits. Higher STAI scores suggest higher levels of anxiety.  The most recent version is the State-Trait Anxiety Inventory for Adults™ (STAI-AD). Although originally based on English language words, the STAI subsequently has been translated and adapted into more than 40 different languages including, for example, Chinese, Danish, Dutch, Finnish, French, Italian, Norwegian, Portuguese, Spanish, Swedish, and Thai. The STAI was revised into its current form in 1983. The STAI can be administered across a range of socio-economic status levels and requires only a sixth grade reading level. It is used (along with other measures) in making diagnoses and distinguishing between anxiety and depression, in clinical settings, as well as in research.
Spielberger also constructed other self-report state-trait scales purported to measure various other emotions and dispositions such as the State-Trait Anxiety Inventory for Children (STAIC), the State-Trait Curiosity Inventory (STCI), the State-Trait Anger Scale (STAS), the State-Trait Anger Expression Inventory (STAXI), and the State-Trait Personality Inventory (STPI).
- 1 State Anxiety (A-State)
- 2 Trait Anxiety (A-Trait)
- 3 Forms
- 4 Scoring
- 5 State-Trait Anxiety Inventory Sample Items
- 6 Additional Scales
- 7 State-Trait Personality Inventory (STPI)
- 8 References
State Anxiety (A-State)
State anxiety (A-State) can be defined as fear, nervousness, discomfort, and the arousal of the autonomic nervous system induced temporarily by situations perceived as dangerous (i.e., how a person is feeling at the time of a perceived threat).
Examples: A child feels anxious when confronted by a large, strange animal. A person feels anxious to get on an airplane for the first time.
Trait Anxiety (A-Trait)
Trait anxiety (A-Trait) can be defined as a relatively enduring disposition to feel stress, worry, and discomfort.
Examples: A child experiences anxiety in social situations and is always anxiety prone throughout their childhood and adulthood. A person experiences anxiety in an array of normal situations such as going to the grocery store or going to work.
The STAI comprises 40 items, and distinguishes between a person’s state and trait anxiety levels. The A-Trait and A-State scales comprise 20 items each, scored on a 4-point Likert-type response scale.
State-Trait Anxiety Inventory (Form X)
The original Form X of the STAI was revised resulting in Form Y.
State-Trait Anxiety Inventory (Form Y)
Form Y of the STAI is a more popular version with improved psychometric properties.
State-Trait Anxiety Inventory (STAI-6)
Both the A-State and A-Trait scales comprise 20 items each and are scored on 4-point forced-choice Likert-type response scales. Scores range from 20 to 80, with higher scores suggesting greater levels of anxiety. Low scores suggest mild anxiety, median scores suggest moderate anxiety, while high scores suggest severe anxiety. Both scales include direct and reverse-worded items. Direct-worded items represent the presence of anxiety in a statement such as "I feel worried." Reverse-worded items represent the absence of anxiety in a statement such as, "I feel secure."
The 4-point A-State intensity response scale is as follows:
- not at all
- moderately so
- very much so.
The 4-point A-Trait frequency response scale is as follows:
- almost never
- almost always.
State-Trait Anxiety Inventory Sample Items
- Anxiety Absent
- "I am calm."
- "I feel secure."
- Anxiety Present
- "I am tense."
- "I am worried."
- Anxiety Absent
- "I am content."
- "I am a steady person."
- Anxiety Present
- "I worry too much over something that really doesn’t matter." 
The STAIC (a downward extension of the STAI) can be administered to children up to junior high school level (aged 9-12 years). If necessary, the items can be verbally read out to younger children. Spielberger also constructed other self-report scales, including the State-Trait Anger Scale (STAS) and its short-form (STAS-6), the State-Trait Anger Expression Inventory (STAXI), and the State-Trait Personality Inventory (STPI), 
State-Trait Anger Scale (STAS)
Anger is an emotional state when feelings can vary in intensity, from irritation, to annoyance, to the extremes of fury or rage. This differs from hostility and aggression in that anger is much less complex than hostility or aggression, while both of these states can include feelings of anger.
The STAS is very similar in format to the STAI. However, this scale was formed instead to measure anger as an emotional state and how prone to anger people are.
This scale measures both state and trait anger, it is similar to the STAI in assessing state and trait emotions. State anger (S-Anger) is a psychobiological state or condition. This state consists of varying intensities of anger. It is assumed that S-Anger would change over time, based on the situations of the person. Trait anger (T-Anger) is defined by the individual differences in how often that S-Anger was experienced over time.
State-Trait Anger Expression Inventory (STAXI-2)
The STAXI-2 (revised 2nd edition) purports to measure an individual's experience, expression, and control of anger. The STAXI-2 includes self-report scales purported to measure State Anger, Trait Anger, Anger Expression-Out, Anger Expression-In, Anger Control-Out, Anger Control-In, and Anger Expression Index. Ratings are on a 4-point forced-choice response scale. The State Anger scale measures transient anger intensity, while the Trait Anger scale measures the frequency of angry feelings. The Anger Expression-In scale measures the extent to which one “holds things in” or suppresses anger, whereas the Anger Expression-Out scale measures the actual expression of aggression. The Anger Control-In scale measures the extent to which the suppression of anger is controlled, whereas the Anger Control-Out scale measures the constraint of overt anger expression. Even when the overt expression of anger (Anger-out) is minimal, the STAXI-2 can capture anger that may be present where Anger-in scores are high. A person’s handling of anger may lie between overcontrol and undercontrol which the STAXI-2 can help identify. The STAXI-2 comprises 57 items, which make up 7 separate scales as follows:
- S-Anger: 15 items
- T-Anger: 10 items
- AX/In: 8 items; Measures how often feelings of anger are experienced and are held in and not acted on.
- AX/Out: 8 items; Measures how often feelings of anger are acted upon towards people or objects.
- ACon/In: 8 items; Measures how often an individual tries to control of suppressed anger.
- ACon/Out: 8 items; Measures how often an individual tries to control the outward expression of anger.
- AX: 24 items; Measures how often anger is generally being experienced and expressed.
Psychometric Properties: Item Homogeneity: Based on the STAXI-2 normative sample (N > 1,900), a median Cronbach alpha coefficient of .87 for the STAXI-2 has been reported, with alphas for the AX index ranging from .75 to .82. High alpha coefficients however may be indicative of a narrow scale with little breadth of measurement of the relevant construct/factor.
Reliability: Over a two-month interval, test-retest (stability) coefficients for a French adaptation of the STAXI-2 (N = 139) were found to be .70 for the trait anger scale and .32 for the state anger scale, respectively (in accord with state-trait theory).
Validity: In regard to construct/factor analytic validity, several exploratory and confirmatory factor analytic studies have provided empirical support for the claimed STAXI-2 structure. Likewise, several studies have provided predictive validity evidence for the STAXI-2.
State-Trait Personality Inventory (STPI)
Variable The STPI is useful for measuring the four affects of anxiety, depression, anger and curiosity. The STPI measures these constructs both as traits/dispositions and as transitory emotions/states. Trait and state measures may be employed as outcome variables in evaluation of therapeutic interventions. However, the STPI provides measures of only four affect dimensions in comparison with the more comprehensive mapping of affect dimensions by Izard et al.
Description The 80-item STPI includes 10 items for each of eight state-trait scales. The STPI was derived from the State-Trait Anxiety Inventory (STAI), and the State-Trait Anger Expression Inventory (STAXI). For state items, instructions are to respond as to one’s present feelings "at this very moment" on a 4-point response scale. For trait items, instructions are to respond as to how one generally feels. As with the single-dimension scales (STCI, STAI, STAS, STDI), the STPI items are mainly adjective ratings.
Reliability Internal Consistency Spielberger and Reheiser reported Cronbach alpha coefficients for the state-trait anger scales ranging from .87 to .93, and for the state-trait depression scales a median alpha of .90. They reported a median alpha coefficient of .93 for the state A-state scale, and for the A-trait scale, .90.
Test-Retest Reliability Stability coefficients for the A-Trait scale were found to range from .73 to .86 across 3-15 week intervals, whereas the median stability coefficient for the A-State scale was .33 as would be expected for a situationally sensitive measure. Thus, two-week stability coefficients for the state anger scale were .27 (males) and .21 (females), while for the trait anger scale .70 (males) and .77 (females). Evidently, the STPI state scales appear to be sensitive to transitory fluctuations in emotional states, and as would be expected, the stability coefficients for the state scales are lower than those for the trait scales.
For example, the trait depression scale exhibited an overall median correlation of .78 with the Beck Depression Inventory (BDI), the Zung Self-Rating Depression Scale (ZUNG), and the Center for Epidemiological Studies Depression Scale (CES-D)—(for a psychometric review of these scales, see Boyle). The corresponding median correlation with the state depression scale was .66. Spielberger and Reheiser also found that the A-trait scale correlated .73 with the Taylor Manifest Anxiety Scale (TMAS), and .85 with the Cattell Anxiety Scale Questionnaire (ASQ).
Divergent/Discriminant Validity Spielberger reported that state anxiety and state anger correlated negatively with social desirability (-.14 and -.33, respectively).
Construct/Factor Analytic Validity Spielberger and Reheiser reported that separate factor analyses of the STPI scales supported the state-trait distinction.
Criterion/Predictive Validity The STAI scales correlate with impaired performance and attentional bias. Trait anger correlates with elevated blood pressure. Matthews et al. showed that the STPI A-Trait scale correlated .40 with viewing frequency of threat stimuli. Wrenn et al. conducted a prospective cohort study of 1968 survivors of myocardial infarction using the STPI anxiety and anger scales, and found that anxiety predicted higher mortality risk over 10 years. Cromley et al. reported that the STPI trait anxiety and trait anger scales exhibited correlations with lower body satisfaction of .76 and .90 respectively.
Note. The STPI is available from: Mind Garden, Inc., 855 Oak Grove Avenue, Suite 215, Menlo Park, CA 94025 USA. http://www.mindgarden.com/products/staisad.htm (Retrieved August 6, 2015).
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