Shortening the State-Trait Anxiety Inventory

Area of Science:

• Psychometrics
• Clinical Psychology
• Health Psychology

Background:

• Questionnaires for severely ill patients must be concise.
• Abridged versions of psychological inventories are practical for clinical research.
• Assessing anxiety is crucial in various patient populations.

Purpose of the Study:

• To develop short, reliable versions of the State and Trait Anxiety Inventory (STAI).
• To investigate the feasibility of predicting full-scale scores from abbreviated versions.
• To evaluate the impact of shortening on the psychometric properties of the STAI.

Main Methods:

• Utilized data from 444 subjects across three samples: cancer patients, medical students, and surgical patients.
• Employed a stepwise regression procedure to identify key items for predicting total scores.
• Calculated Cronbach's alpha to assess the reliability of the abridged scales.

Main Results:

• A reliable prediction of STAI total scores was achieved using weighted sums of eight items per scale.
• Omitting weights resulted in minimal information loss.
• Cronbach's alpha for the State scale decreased from 0.93 to approximately 0.85, and for the Trait scale from 0.91 to approximately 0.82.
• The relationship between the State and Trait scales was minimally affected by the shortening process.

Conclusions:

• Shortened versions of the STAI can be reliably used in studies with severely ill patients.
• The developed eight-item scales offer a practical alternative for anxiety assessment.
• The findings support the use of abridged inventories to enhance efficiency in clinical research without significant loss of information.