Payment
Study guides: Exam FAM, Exam RET-101
The payment Y (the insurer's payment) is the amount an insurer actually pays a policyholder after all policy adjustments — deductible, coinsurance, and benefit limit — are applied to the raw loss X.
Y = \min\!\big(c\,(X - d)^+,\ u\big)
Xis the ground-up loss,dthe deductible,cthe coinsurance factor, anduthe benefit limit (maximum payment).(X - d)^+ = \max(X - d,\ 0)applies the deductible; multiplying bycapplies coinsurance; the outer\mincaps the payment atu.- This is the payment random variable whose expectation drives premium and reserve calculations.
Expected Payment with a Deductible A loss
Xis uniformly distributed on[0, 1000]with a $200deductible and no other adjustments. FindE[Y].Answer Here
Y = (X - 200)^+: zero forX \le 200, andX - 200forX > 200.\begin{align*} E[Y] &= \int_{200}^{1000} (x - 200)\,\frac{1}{1000}\,dx \\ &= \frac{1}{1000} \cdot \frac{(800)^2}{2} \\ &= \frac{640{,}000}{2{,}000} = 320 \end{align*}The insurer expects to pay $
320per loss after the deductible.