It's critical that property-casualty insurance companies focus on the "economic combined ratio" as a key measure of profitability in the current low-interest rate environment, according to a new study by Swiss Re.

The reason the combined ratio is assuming new importance in measuring profitability is that the contribution of underwriting to overall profitability over the last 10 years for p-c insurers worldwide was "small," the study said.

The new study--"Measuring Underwriting Profitability of the Nonlife Insurance Industry"--introduced the economic combined ratio as an alternative measure of underwriting profitability.