Loss Frequency Trend
Loss frequency trend classifies whether an operation's rate of claims per exposure unit has been increasing, stable or decreasing over recent policy years, giving underwriters a forward-looking signal beyond the raw claims count.
- Category
- History
- Data type
- Enumeration
- Risk drivers
- Frequency, Accumulation
- Underwriting impact
- Premium, Deductible, Condition/Warranty
Typical proposal-form questions
- Has the number of claims per unit of exposure (e.g. per CHF 1m turnover, per employee, per vehicle) increased, remained stable or decreased over the last 3-5 policy years?
- If frequency has increased, is this attributable to business growth, a specific new activity, or a genuine deterioration in loss experience?
- Has exposure (turnover, headcount, fleet size) changed materially over the same period, and has frequency been normalised accordingly?
Evidence
- Multi-year loss run report with exposure data by policy year
- Actuarial or broker trend analysis normalising frequency by exposure
- Underwriter's year-on-year claims development commentary
Why it matters for underwriting
A raw count of claims over several years can be misleading on its own, since it does not distinguish an operation that is simply growing, and therefore generating more claims in absolute terms, from one whose underlying risk is genuinely deteriorating. The loss frequency trend normalises claims by an exposure base such as turnover, headcount, sum insured or fleet size, and classifies the resulting direction as increasing, stable or decreasing, giving underwriters a forward-looking signal about whether current controls and risk management are holding, improving or losing ground against the exposure.
Capturing the attribute and evidence
Underwriters derive the trend from a multi-year loss run that includes exposure data for each policy year, allowing frequency to be calculated per exposure unit rather than in absolute terms. Where available, an actuarial or broker-prepared trend analysis normalises the figures and separates genuine frequency change from exposure growth or seasonality. The underwriter’s own year-on-year development commentary, discussed with the risk manager at renewal, typically explains any material shift and identifies whether it stems from a specific new activity, location or process change.
Effect on coverage, premium and conditions
A stable or decreasing frequency trend, particularly alongside growing exposure, supports premium credits and confirms the effectiveness of existing risk controls. An increasing trend that cannot be explained by exposure growth alone typically leads to premium loading, deductible increases, or specific conditions targeting the activity, location or process identified as the source of the deterioration.
Mitigation measures
Where frequency is trending upward, insurers and risk engineers typically require a root-cause analysis of the recent claims driving the trend, targeted process or training interventions at the identified source, and a follow-up review at the next renewal to confirm the trend has stabilised or reversed.
Standards and codes
- ISO 31000:2018 – Risk management, Guidelines