Morbidity Tables and Disability Rate Assumptions

Morbidity Table Construction

Morbidity tables quantify the rates at which people become sick, disabled, or require medical care. Unlike mortality tables that track a single event (death), morbidity tables must capture incidence rates, recovery rates, and duration of disability. The SOA publishes standard tables such as the 2012 Individual Disability Insurance (IDI) valuation table, which provides claim incidence and termination rates by age, gender, occupation class, and benefit period.

Building a morbidity table requires large volumes of claims data, often spanning a decade or more. The actuary must define what constitutes a qualifying disability event, account for changes in policy definitions over time, and adjust for trends in claim reporting behavior. The resulting table is multi-dimensional, varying by age at disability, duration of disability, occupation class, elimination period, and benefit period. This complexity is what distinguishes morbidity modeling from mortality modeling, where the event being tracked is more straightforward to define and observe.

Incidence Rates

Incidence rates measure the probability that an insured person becomes disabled during a given year. These rates vary significantly by age, gender, and occupation. For example, a 35-year-old office worker might have an annual incidence rate of 0.3%, while a 55-year-old construction worker could have a rate of 2.0% or higher. Incidence rates generally increase with age as the risk of chronic conditions like back problems, heart disease, and mental health disorders rises.

The definition of disability in the policy contract strongly influences incidence rates. "Own occupation" definitions, which consider a person disabled if they cannot perform their specific job, produce higher incidence rates than "any occupation" definitions, which require inability to perform any job for which the person is reasonably suited by education and experience. Many policies use own occupation for an initial period (often two years) and then switch to any occupation.

Continuance Rates and Claim Termination

Once a claim begins, the actuary must estimate how long it will last. Continuance rates describe the probability that a claimant remains disabled at each duration after the onset of disability. Claims can terminate through recovery, death, or reaching the end of the benefit period. Recovery rates are highest in the early months of a claim and decline over time. A claimant who has been disabled for two years is much less likely to recover than one who has been disabled for two months.

Claim termination tables typically show monthly termination rates by duration of disability. For a 90-day elimination period policy, the monthly recovery rate might be 5% to 8% in the first year of benefits, declining to 1% to 3% by the third year, and less than 1% per month for long-duration claims. Mental health claims often have higher early recovery rates but can also produce very long duration claims that resist treatment.

Key Assumptions in Disability Pricing

Disability insurance pricing requires assumptions for incidence (the probability of becoming disabled), continuance (how long claims last), and benefit offsets (reductions from other income sources). Elimination period selection significantly affects both incidence and continuance rates. Occupation class is among the strongest predictors, with white-collar workers experiencing lower incidence but potentially longer claim durations than manual laborers.

The elimination period is the waiting period before benefits begin. Common choices are 30, 60, 90, and 180 days. Longer elimination periods reduce both the frequency of claims (because short-term disabilities resolve before benefits start) and the average cost of claims that do qualify. A 180-day elimination period might reduce the premium by 30% to 40% compared to a 30-day period.

Common Pitfalls

One common mistake in disability pricing is applying a single set of morbidity assumptions across all occupations without sufficient differentiation. The difference in claim experience between a desk worker and a heavy manual laborer can be a factor of three or more. Another pitfall is ignoring the impact of economic conditions on disability claims. During recessions, claim incidence tends to rise and recovery rates tend to fall, as unemployed claimants have less financial incentive to return to work.

Actuaries should also be cautious about the trend toward mental health claims, which have become an increasingly large share of total disability claims. These claims present unique challenges because diagnosis is more subjective, treatment outcomes are less predictable, and the stigma associated with mental health can affect both reporting and recovery patterns.

Study Tips

For exam preparation, make sure you understand the multi-state model framework often used in disability insurance, where a person transitions between active, disabled, and recovered (or deceased) states. Practice working with incidence and continuance tables to calculate expected claim costs. Understand how elimination periods and benefit periods interact to determine the net premium for a disability policy. Review the SOA's published valuation tables and know the key dimensions along which rates vary. Finally, be prepared to discuss how economic and social trends can shift morbidity experience over time.