IBNR claims, is determined in aggregate using a paid loss development method rather than on the individual claimant basis that we use for reported claims on long-term products. The average length of time between the event triggering a claim under a policy and the final resolution of those claims is much shorter for these products than for our long-term liabilities and results in less estimation variability. 

Claim reserves for Unum US group life and accidental death and dismemberment products are related primarily to death claims reported but not yet paid, IBNR death claims, and a liability for waiver of premium benefits. The death claim reserve is based on the actual face amount to be paid, the IBNR reserve is calculated using the paid loss development method, and the waiver of premium benefits reserve is calculated using the tabular reserve methodology. 

Claim reserves supporting the group and individual dental and vision products reported in our Unum US and Colonial Life segments have a short claim payout period. As a result, the reserves, which primarily represent IBNR and a small amount of claims pending payment, are calculated using the paid loss development method. 

Claim reserves supporting our Unum International segment are calculated using generally the same methodology that we use for Unum US disability and group term life reserves. Claim reserves for our Unum UK group dependent life product are calculated using discounted cash flows, based on our assumptions for claim duration and discount rates. The assumptions used in calculating claim reserves for this segment are based on standard country-specific industry experience, adjusted for our own experience. 

The majority of the Colonial Life segment lines of business have short-term benefits, which generally have less estimation variability than our long- term products because of the shorter claim payout period. Our claim reserves for Colonial Life's lines of business are predominantly determined using the incurred loss development method based on our own experience. The incurred loss development method uses the historical patterns of payments by loss date to predict future claim payments for each loss date. Where the incurred loss development method may not be appropriate, we estimate the incurred claims using an expected claim cost per policy or other measure of exposure. The key assumptions for claim reserves for the Colonial Life segment lines of business are the timing, rate, and amount of estimated future claim payments; and the estimated expenses associated with the payment of claims. 

