Table of Contents Periodic Reserve Reviews 22 Our recorded reserves are management's best estimate. In order to provide an indication of the variability associated with our net reserves, the following discussion provides a sensitivity analysis that shows the approximate estimated impact of variations in significant factors affecting our reserve estimates for particular types of business. These significant factors are the ones that we believe could most likely materially affect the reserves. This discussion covers the major types of business for which we believe a material deviation to our reserves is reasonably possible. There can be no assurance that actual experience will be consistent with the current assumptions or with the variation indicated by the discussion. In addition, there can be no assurance that other factors and assumptions will not have a material impact on our reserves. The key assumptions fundamental to the reserving process are often different for various reserve groups and accident or policy years. Some of these assumptions are explicit assumptions that are required of a particular method, but most of the assumptions are implicit and cannot be precisely quantified. An example of an explicit assumption is the pattern employed in the paid development method. However, the assumed pattern is itself based on several implicit assumptions such as the impact of inflation on medical costs and the rate at which claim professionals close claims. As a result, the effect on reserve estimates of a particular change in assumptions typically cannot be specifically quantified, and changes in these assumptions cannot be tracked over time. Currently, our recorded reserves are modestly higher than the actuarial point estimate. For Commercial, Specialty and International, the difference between our reserves and the actuarial point estimate is primarily driven by uncertainty with respect to immature accident years, claim cost inflation, changes in claims handling, changes to the tort environment which may adversely affect claim costs and the effects from the economy. For Corporate & Other, the difference between our reserves and the actuarial point estimate is primarily driven by the potential tail volatility of run-off exposures. The reserve analyses performed by our actuaries result in point estimates. Each quarter, the results of the detailed reserve reviews are summarized and discussed with senior management to determine the best estimate of reserves. Senior management considers many factors in making this decision. Our recorded reserves reflect our best estimate as of a particular point in time based upon known facts and circumstances, consideration of the factors cited above and our judgment. The carried reserve differs from the actuarial point estimate as discussed further below. For other more complex reserve groups where the above methods may not produce reliable indications, we use additional methods tailored to the characteristics of the specific situation. For many exposures, especially those that can be considered long-tail, a particular accident or policy year may not have a sufficient volume of paid losses to produce a statistically reliable estimate of ultimate losses. In such a case, our actuaries typically assign more weight to the incurred development method than to the paid development method. As claims continue to settle and the volume of paid loss increases, the actuaries may assign additional weight to the paid development method. For most of our products, even the incurred losses for accident or policy years that are early in the claim settlement process will not be of sufficient volume to produce a reliable estimate of ultimate losses. In these cases, we may not assign much, if any, weight to the paid and incurred development methods. We may use the loss ratio, Bornhuetter-Ferguson and/or frequency times severity methods. For short-tail exposures, the paid and incurred development methods can often be relied on sooner, primarily because our history includes a sufficient number of years to cover the entire period over which paid and incurred losses are expected to change. However, we may also use the loss ratio, Bornhuetter-Ferguson and/or frequency times severity methods for short-tail exposures. Stochastic modeling produces a range of possible outcomes based on varying assumptions related to the particular reserve group being modeled. For some reserve groups, we use models which rely on historical development patterns at an aggregate level, while other reserve groups are modeled using individual claim variability assumptions supplied by the claims department. In either case, multiple simulations using varying assumptions are run and the results are analyzed to produce a range of potential outcomes. The results will typically include a mean and percentiles of the possible reserve distribution which aid in the selection of a point estimate. analysis of the impact of large losses and claim cost trends based on changes in the cost of repairing or replacing property, changes in the cost of medical care, changes in the cost of wage replacement, judicial decisions, legislative changes and other factors.