Item response theory and differential item functioning analyses with the suicidal behaviors questionnaire: Revised in US and Chinese samples

Background: Despite the widespread use of the Suicidal Behaviors Questionnaire-Revised (SBQ-R) and advances in item response theory (IRT) modeling, item-level analysis with the SBQ-R has been minimal. Aims: This study extended IRT modeling strategies to examine the response parameters and potential differential item functioning (DIF) of the individual SBQ-R items in samples of US (N = 320) and Chinese (N = 298) undergraduate students. Method: Responses to the items were calibrated using the unidimensional graded response IRT model. Goodness-of-fit, item parameters, and DIF were evaluated. Results: The unidimensional graded response IRT model provided a good fit to the sample data. Results showed that the SBQ-R items had various item discrimination parameters and item severity parameters. Also, each SBQ-R item functioned similarly between the US and Chinese respondents. In particular, Item 1 (history of attempts) demonstrated high discrimination and severity of suicide-related thoughts and behaviors (STBs). Limitations: The use of cross-sectional data from convenience samples of undergraduate students could be considered a major limitation. Conclusion: The findings from the IRT analysis provided empirical support that each SBQ-R item taps into STBs and that scores for Item 1 can be used for screening purposes.