Using polytomous item response models to assess death anxiety.
BACKGROUND
: The study of human attitudes toward death has given rise to a substantial body of empirical research. Psychometric instruments have been developed to measure fear of death, or death anxiety, and its psychological consequences in people who continually come into contact with stimuli related to mortality.


OBJECTIVE
: To analyze the 20-item Death Anxiety Inventory (DAI) within the framework of item response theory (IRT) and using the generalized partial credit model.


METHODS
: The sample comprised 154 men and 550 women and was drawn from nurses, doctors, industrial workers, teachers, undergraduates, and retired persons. Subjects completed the DAI, a self-administered, Likert-type questionnaire of 20 items, each with six response options.


RESULTS
: The DAI showed a relatively adequate fit to the generalized partial credit model. Thus, 4 of the 20 items presented a poor fit to the model. The analysis of item information and test information functions revealed that the 20-item test was appropriate for differentiating subjects with medium or high levels of death anxiety. The test information function was higher in this range of scores, indicating greater precision in the estimate of death anxiety for these subjects.


CONCLUSIONS
: The generalized partial credit model can be used to obtain detailed information about a clinical test and its items, and there are advantages to this approach when working with polytomous tests.
Gómez
Juana
J
Department of Behavioral Sciences Methodology, University of Barcelona, Spain.
Hidalgo
M Dolores
MD
Tomás-Sábado
Joaquín
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D001007:Anxiety / Q000175:diagnosis* / Q000209:etiology / Q000523:psychology; D001293:Attitude to Death; D016002:Discriminant Analysis; D005163:Factor Analysis, Statistical; D005178:Faculty; D005239:Fear; D005260:Female; D006282:Health Personnel / Q000523:psychology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D009730:Nursing Assessment / Q000379:methods / Q000592:standards; D015403:Nursing Evaluation Research; D011237:Predictive Value of Tests; D011594:Psychometrics; D012720:Severity of Illness Index; D013030:Spain; D013334:Students / Q000523:psychology; D011795:Surveys and Questionnaires / Q000592:standards*