# Modelling Prefabricated Construction Safety
## 4 Conclusions  
This is a pioneer study to model PCS based on accident frequency from 2017-2022 in a New Zealand context. The modelling for PCS is simplistic as well predictive driven from accident frequency. Figure 19: ARIMA models for accident forecasting by injury site (2017–2027). The simplistic modelling covers the accident index, accident frequency rate, and elemental safety. * The accident index has been relatively steady over the years for offsite in comparison to onsite. However, it was found that the workforce offsite has a 0.9 times chance while onsite has a 3.4 times chance to encounter accident situations at any hour of the day at workplaces. * The accident frequency rate is almost twice as high as for offsite in comparison to onsite due to a smaller workforce. * The ranking of the top business classifications by cost of safety, in ascending order, is Wood_S, Conc, Alum, and Metal_S. It was found the cost of safety for offsite is almost a third of the onsite cost. * The most vulnerable occupations across all business classifications are 'carpenters and joiners', 'labourers', and 'building and related workers'. However, the situation somehow varies for individual business classifications. Furthermore, the weightage of accidents for each occupation was determined under each classification. Interestingly, it was found that the occupations 'carpenters and joiners' and 'labourers' are safer offsite. * The most common types of injuries offsite are'soft tissue' and 'laceration/puncture/sting'. However, multiple injury types are associated with business classifications. Furthermore, the weightage of injury types for each occupation was determined under each classification. * The most common injury cause is 'lifting/carrying/strain', but less than half are associated with other causes. All injury causes offsite range from three to five times lower than that of onsite. Furthermore, the weightage of injury causes was determined under each classification. * The most common prior activities to encounter injuries are 'employment task' and 'lifting/lowering/loading/unloading'. Injury prior activities offsite range from three to six times lower that for onsite. Furthermore, the weightage of prior activity to injury for each occupation was determined under each classification. * Primary injury sites on the human body are 'lower back/spine' and 'finger/thumb'. However, the trend varies for other business classification types. Interestingly, primary injury sites offsite range from three to eighteen times lower than that for onsite for all types. Furthermore, the weightage of primary injury sites for each occupation was determined under each classification. Simplistic modelling is applied to understand the nature and criticality of the accidents. This knowledge is potentially used in the strategic orientation of current and new companies regarding H&S. Furthermore, accident information helps in project planning and risk management. In predictive modelling, the current and future accident frequency trends were determined and forecasted, respectively. * Accidents are predicted to increase in companies for Alum, and Wood_P, but there will be a decline for Wood_S, Conc, and Metal_S. However, Metal_P will somehow remain steady. Overall, offsite will most likely see a gradual decrease, but onsite will have a fluctuating increase. * The most vulnerable occupations have an increasing trend for'sheet metal workers' under Metal_S and 'carpenters and joiners' under Wood_P. However, three of the occupations will likely decline, such as 'carpenters and joiners' under Wood_S, 'operators' under Conc, and 'building and related workers' under Alum. Interestingly, the 'labourer' under Metal_P will be steady. * There is an increasing trend for injury types for 'foreign body orifice or eye' and 'fracture or dislocation'. However, there will likely be a decline in 'laceration/puncture/sting' and 'industrial deafness', but'soft tissue' will be steady.