Zenith is the latest insurer to invest in claims assessment technology from Insurance Services Office (ISO).
Claims Outcome Advisor cross-references policyholders' injury claim details with a database of over 18,000 injuries and 14,000 occupations to give insurers an accurate pay-out sum.
Admiral, Chaucer, Zurich and Highway already use the system. ISO claims it has cut claims costs for Highway and Chaucer by 14% and 16% respectively.
Joe Pendle, ISO UK's client services director, said the system gave insurers "an accurate and consistent figure which slashes claims costs by over 10% and allows them to better understand their exposures".