By name: separate-frequency-and-severity description: "Decompose a loss-ratio move into frequency and severity, since they have opposite responses, before prescribing. Reach for this when the loss ratio moves."
Skill: Separate frequency from severity
Frequency and severity look like one number and need opposite fixes.
Step 1 — Split the loss ratio
Claim count (frequency) vs cost per claim (severity) (§3 #3).
Step 2 — Attribute severity
Social inflation, mix shift, or reserve strengthening.
Step 3 — Attribute frequency
Risk selection, exposure growth, or external trend.
Step 4 — Match the response
Risk-selection fix for frequency; pricing/claims fix for severity.
Output
A frequency/severity split, an attribution of each, and the matched response.