2.2.3. Intolerance of Uncertainty Scale (IUS-12)

The Italian HCWs' intolerance of uncertainty was assessed using the Italian version [86] of IUS-12 [87]; it is the short version of the 27-item intolerance of uncertainty scale (IUS-27 [88]), developed to evaluate "emotional, cognitive and behavioral reactions to ambiguous situations, implications of being uncertain, and attempts to control the future" [88] (p. 791). IUS-12 is a two-factor scale that represents two different sub-dimensions of intolerance toward uncertainty: prospective and inhibitory [49,87]. The former reflects "desire for predictability and active engagement in information seeking to increase certainty"; the latter reflects "uncertainty avoidance and paralysis in the face of uncertainty" [89] (p. 377). Respondents assess the items on a five-point Likert scale, ranging from 1 (not at all characteristic of me) to 5 (entirely characteristic of me).

Both the Cronbach's alpha and McDonald's omega were 0.90 for the overall scale; Cronbach's alpha for prospective intolerance of uncertainty (items 1–7) was 0.83 and McDonald's omega was 0.84, while alpha and omega for inhibitory intolerance (items 8–12) were 0.90.
