Lawyer Monthly - January 2023

for the calculation of an individual’s life expectancy? The easiest method is to use the constant relative risk (RR) method. This method relies on the assumption that the relative risk of dying with a medical condition stays constant with increasing age. This method overestimates the risk of dying with most chronic medical conditions, leading to calculated mortality rates that are generally too high at older ages, reducing the true life expectancy associated with a medical condition. Although this method is valid for some medical conditions such as spinal cord injury under the age of 50 years, the constant RR method decreases the estimates of life expectancy for most chronic medical conditions. This biased method is nevertheless commonly used in the life insurance industry, as building a life insurance rating on a biased shorter survival will favour the life insurance company. As most life expectancy experts are (or have been) life insurance underwriters, this biased method is commonly used, although it should definitely be banned from the litigation field. In that case, what is the best method to calculate a life expectancy to be used by the Court? For most chronic medical conditions, such as diabetes or coronary artery disease, the risk of an early death is not constant, but decreases with older ages. Thus, a patient under the age of 40 years having a heart attack will have a high predicted mortality in the years immediately following his heart attack; but if this patient has already survived up to the age of 70 years, the excess risk of dying will be far lesser. For most chronic medical conditions, there are two methods that will give unbiased life expectancies closer to the true life expectancies associated with such a chronic medical condition. These are the log-linear declining relative risk (LDR) method and the proportional life expectancy (PLE) method (my preferred method). Although these two methods should be used routinely by experts, this is rare to see. Can you calculate the life expectancy of an individual having several medical conditions reducing their likelihood of survival? The first challenge is to select all the medical conditions reducing life expectancy in the medical brief. Lengthy experience in the field of life underwriting is an advantage when it comes to identifying all of the medical conditions associated with a reduced survival. But here, again, most experts – being EXPERTWITNESS 57 Lengthy experience in the field of life underwriting is an advantage when it comes to identifying all of the medical conditions associated with a reduced survival.

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