Speaker
Description
The Sniffin’ Sticks Test (SST) is one of the most widely used tools for assessing olfactory function in research and clinical settings. However, despite its widespread use, a detailed psychometric evaluation of its items remains limited. Understanding the item functioning within the identification subtest is crucial to ensure the test's reliability, validity, and applicability across different populations. This study applies Item Response Theory (IRT) to evaluate the psychometric properties of the SST's identification subtest, identifying potential weaknesses and areas for improvement in the measurement of olfactory function. 397 participants (60.5% female; mean age and SD = 44.62 +/- 18.33) completed the identification subtest of the SST. Item functioning was analyzed using a one-parameter (1PL) and a two-parameter (2PL) logistic IRT model, estimating item difficulty and discrimination parameters. Differential Item Functioning (DIF) analysis was conducted to investigate potential differences in item performance between males and females. Items with poor discrimination or extreme difficulty values were identified as candidates for revision or removal to enhance the overall measurement accuracy of the test. Model comparison revealed that the 2PL IRT model provided the best fit to the data. Results of the 2PL IRT analysis indicated that at least three items (leather, turpentine, and pineapple) had low discrimination parameters, while DIF analysis suggested that one item (anis) worked differently across sexes. In conclusion, the application of an IRT approach proved useful in enhancing the precision and reliability of the Sniffin’ Sticks Test.
