Simon Folkard

I was the 2004 “Visiting Scholar” at the Liberty Mutual Research Institute for Safety (LMRIS) in Hopkinton, USA.   While at LMRIS I was continually impressed by the friendliness of the researchers there and the general spirit of collaboration rather than competition that existed.   Researchers from different disciplines were very open about their ideas and ongoing research, and only too willing to give of their time and expertise.

Historically, my research interests had been in the impact of abnormal work/rest schedules, such as shift work, on mood and performance.  However, despite my lack of expertise, the practical implications for work scheduling had led me to conduct a number of  rather crude epidemiological studies examining the impact of various features of shift systems on the risk of occupational injuries.  When Dr. David Lombardi contacted me out of the blue with questions regarding my research I little realised what would result from it.   After several exchanges of ideas and information he suggested that I apply to become a Visiting Scholar at LMRIS, and it seemed to me like a heaven-sent opportunity to collaborate with a highly regarded epidemiologist who had overlapping interests to mine.  We collaborated closely on the development of a “Risk Index” that mathematically combined the influence of the different shift system features into a single relative risk estimate.  Since then, we have collaborated closely with one another on a number of papers that have examined the   temporal influences on the risk of occupational injuries, culminating in a just-published update of our original Risk Index by Dorothee Fischer et al.   The jointly-authored publications (most of which are available on that have arisen for our continued collaboration include:


  • Folkard, S. & Lombardi, D.A. (2004).   Designing safer shift systems.   In P Nickel, K Hänecke, M Schütte and H Grzech-Šukalo, (Eds.) Aspekte der Arbeitspsychologie aus Wissenschaft und Praxis. Pp 151-166. Lengerich: Pabst Science Publishers.


  • Folkard, S. & Lombardi, D.A. (2004).   Towards a “Risk Index” to assess work schedules. Chronobiology International. 21, 1063-1072.


  • Folkard, S., Lombardi, D.A. & Tucker, P.T.   (2005).    Shiftwork: Safety, Sleepiness and Sleep.  Industrial Health (Japan). 43, 20-23.


  • Folkard, S. & Lombardi, D.A. (2006)   Modelling the impact of the components of long work hours on injuries and “accidents”   American Journal of Industrial Medicine. 49, 953-963.


  • Folkard, S., Lombardi, D.A. & Spencer, M.B. (2006) Estimating the circadian rhythm in the risk of occupational injuries and “accidents”.   Chronobiology International. 23, 1181-1192.


  • Tucker, P., Lombardi, D.A., Smith, L. & Folkard, S. (2006) The impact of rest breaks on temporal trends in injury risk.  Chronobiology International. 23, 1423-1434.


  • Lombardi DA, Folkard S, Willetts JL & Smith GS (2010) Daily sleep, weekly working hours, and risk of work-related injury: US National Health Interview Survey (2004-2008).   Chronobiology International. 27, 1013-1030.


  • Williamson, A., Lombardi, D.A., Folkard, S., Stutts, J., Courtney, T.K. & Connor, J.L. (2011). The link between fatigue and safety.   .Accident Analyses and Prevention. 43. 498-515.


  • Arlinghaus A., Lombardi, D.A., Willetts, J.L., Folkard, S. & Christiani, D.C. (2012) A structural equation modeling approach to fatigue-related risk factors for occupational injury. American Journal of Epidemiology. 176. 597-607.


  • Arlinghaus, A., Lombardi, D.A., Willetts, J.L., Folkard, S. & Christiani, D.C. (2012) Response to Commentary “Structural equation models and epidemiologic analysis” American Journal of Epidemiology. 176. 603-604.


  • Lombardi DA, Wirtz, A., Willetts JL & Folkard S, (2012) Independent effects of sleep duration and body mass index on the risk of a work-related injury: Evidence from the US National Health Interview Survey (2004-2010). Chronobiology International. 29. 556-564.


  • Wirtz, A., Lombardi, D.A., Courtney, T.K., Christiani, D.C., Folkard, S., & Perry, M.J. (2012) The effect of rest breaks on time to injury – a study on work-related ladder-fall injuries in the United States.  Scandinavian Journal of Work, Environment and Health, 38.560-567.


  • Wirtz, A., Lombardi, D.A., Willetts, J.L., Folkard, S. & Christiani, D.C. (2012) Gender differences in the effect of weekly working hours on occupational injury risk in the U.S. working population.  Scandinavian Journal of Work, Environment and Health. 38. 349-357



  • Lombardi DA, Jin K, Vetter C, Courtney TK, Folkard S, Arlinghaus A, Liang Y & Perry MJ (2014). The impact of shift starting time on sleep duration, sleep quality, and alertness prior to injury in the People’s Republic of China Chronobiology International. 31. 1201-1208.


  • Fischer D, Lombardi DA, Folkard S, Willetts J & Christiani DC (2017). Updating the “Risk Index”: A systematic review and meta-analysis of occupational injuries and work schedule characteristics. Chronobiology International.