The Chemical Odor Sensitivity Scale: Reliability and validity of a screening instrument for idiopathic environmental intolerance

ObjectiveThe objective of this study was to examine the psychometric qualities of a brief screening measure for idiopathic environmental intolerance (IEI), the Chemical Odor Sensitivity Scale (COSS).MethodologyThe COSS was administered together with other measures of environmental sensitivity, IEI, and symptom scales in large samples (students, individuals with IEI, and individuals without IEI).ResultsThe COSS achieved high internal consistency (.88≤Cronbach's α≤.96) and good factorial, convergent, and discriminant validity across diverse samples. In a longitudinal sample, the COSS and other IEI features were stable across time. According to receiver operating characteristic analyses, the COSS performs adequately in screening individuals likely to meet case criteria for IEI.ConclusionsThe favorable psychometric qualities of the COSS recommend the scale as a useful tool both for assessing self-reported chemical odor sensitivity as a vulnerability marker and for screening for IEI.