Review of studies that have used the Standard Shiftwork Index: Evidence for the underlying model of shiftwork and health

The Standard Shiftwork Index (SSI) provides shiftwork researchers with a standardised battery for assessing the impact of shiftwork on psychological and physiological well-being. We review the published SSI literature and evaluate the extent to which the results of these publications support the model underpinning the SSI. A total of 70 SSI publications were identified, of which 41 were selected. The 41 studies were published between 1993 and 2006 and had a combined total of 21,420 respondents. The analysis indicated support for parts of the SSI model, particularly in relation to the impact of shift systems design on individual well-being, as well as the role of individual factors (e.g., personality, coping style). However, evidential support for the model as a whole is incomplete. The findings of the reviewed studies are summarised and methodological limitations are discussed.