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## Commercial 

The following table presents further detail of the development recorded for the Commercial segment. 

## Years ended December 31 

<img src='content_image/1044478.jpg'>

## 2018 

Unfavorable development in general liability was driven by higher than expected claim severity in unsupported umbrella in accident years 2013 through 2016. 

Favorable development in workers’ compensation was driven by lower frequency and severity experience and favorable impacts from California reforms. 

Favorable development in property and other was driven by lower than expected claim severity in catastrophes in accident year 2017. 

## 2017 

Favorable development in commercial auto was primarily due to lower than expected severity in accident years 2013 through 2016, as well as a large favorable recovery on a claim in accident year 2012. 

Favorable development in general liability was due to lower than expected severity in life sciences. 

Favorable development in workers’ compensation was primarily related to decreases in frequency and severity in recent accident years, partially attributable to California reforms impacting medical costs. This was partially offset by unfavorable development related to an adverse arbitration ruling on reinsurance recoverables from older accident years as well as the recognition of loss estimates associated with earned premium from a prior exposure year. 

## 2016 

Favorable development in commercial auto was primarily due to favorable settlements on claims in accident years 2010 through 2014 and lower than expected severities in accident years 2012 through 2015. 

Favorable development in general liability was primarily due to better than expected claim settlements in accident years 2012 through 2014, better than expected severity on umbrella claims in accident years 2010 through 2013, and better than expected severity in medical products liability in accident years 2010 through 2015. This was partially offset by unfavorable development related to an increase in reported claims prior to the closing of the three year window set forth by the Minnesota Child Victims Act in accident years 2006 and prior. 

Unfavorable development in workers' compensation was primarily due to higher than expected severity for Defense Base Act contractors that largely resulted from a reduction of expected future recoveries from the US Department of Labor under the War Hazard Act. Further unfavorable development was due to the impact of recent Florida court rulings for accident years 2008 through 2015. These were partially offset by favorable development related to lower than expected frequencies related to our ongoing Middle Market and Small Business results for accident years 2009 through 2014. 

Favorable development in property and other was primarily due to better than expected loss frequency in accident years 2013 through 2015. This was partially offset by unfavorable development related to higher than expected severity from a fourth quarter 2015 catastrophe event. 

