Statistics Quest

Applied case · Insurance · about 75 minutes

Pricing for rare large claims

Measure claim frequency per policy-year, recognise overdispersion, describe a heavy-tailed severity distribution, and price a premium that neither ignores nor over-reacts to one huge claim.

The brief

Sahil Mutual Insurance (a fictional insurer) is re-pricing its private motor book for next year. The pricing actuary has one policy year of data on 1,500 policies. Last year a single claim of SAR 480,000 shocked the management team; the sales director now argues that “claims are usually small — about SAR 6,884 — so the premium can come down”, while the CFO wants a large increase “because of the big claim”.

Your job, as the analyst supporting the actuary:

  1. check the data and put frequency on a fair basis (claims per policy-year);
  2. test whether a simple Poisson model describes how often policyholders claim;
  3. describe the size of claims honestly — including the tail;
  4. propose a pure premium (expected claims cost per policy-year) and explain how to treat the large claim.

The data. insurance_claims has one row per policy: region, driver age band, vehicle value, exposure (the fraction of the year insured), number of claims and total amount claimed. It is synthetic — generated with a documented frequency–severity model and one planted very large claim — and describes no real insurer or policyholder.

Stakeholders. The pricing actuary (signs off rates), the CFO (solvency and profit), sales (competitiveness), and the regulator (premiums must be fair and justified).

Dataset

Motor insurance claims

1,500 rows · one row = one motor policy (one policy year) · synthetic data

PolicyRegionDriver age bandVehicle value (SAR)Exposure (years)Claims (claims)Total claimed (SAR)
POL0001Central36-50168500100
POL0002Eastern51-6527500100
POL0003Western26-35106500100
POL0004Eastern26-351520000.9400
POL0005Western26-35101000128429.6
POL0006Eastern51-65720000.9800

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This case has 4 stages and 10 graded tasks, ending with a written report.

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