Environmental Change	Description	Covariate
Underwriting Practices	Insurer either tightens or loosens its under-	Accident year effects in
	writing criteria due to either changes in the	longitudinal submodel.
	insurer’s underwriting guidelines or changes
	in regulations.
Claims Processing	Insurer either speeds up or slows down the	Calendar year effects in
	claim settlement due to either exterior or	survival submodel.
	interior reasons.
Product Mix	Insurer changes its business mix by increasing	Accident year effects
	or decreasing exposure in long-tail lines of	in both longitudinal
	business.	and survival submodels.