Risk Scoring and Insurance Underwriting: How Carriers Evaluate Property and Liability Exposures

Insurance underwriting is the process of evaluating, classifying, and pricing risk — determining whether to accept a given risk, at what terms, at what price, and subject to what conditions. The underwriting decision is the carrier’s core commercial activity: accept too many bad risks and loss ratios deteriorate; decline too many good risks and premium volume and market share decline. The tools and data sources carriers use to make these decisions have evolved significantly in the past decade, from manual rating tables and field inspection to predictive models, aerial imagery analysis, third-party data integrations, and machine learning scoring systems that process hundreds of variables in seconds.

For the risk data inputs that feed underwriting systems, see Property Risk Assessment: Identifying, Quantifying, and Documenting Insurable Hazards. For the enterprise risk management framework that organizations use to manage their risk profile before it reaches the insurance market, see Enterprise Risk Management: Building a Risk Register and Mitigation Framework.

The Underwriting Process

Property and casualty underwriting follows a consistent process regardless of whether it is automated or manual: risk identification and data collection; risk classification; pricing; terms and conditions determination; and accept/decline decision. The sophistication and speed of each step varies enormously by line of business and risk size — a personal lines homeowner’s policy may be underwritten in seconds by an automated rules engine with no human review; a large commercial property account at $500M in TIV may require 4–6 weeks of underwriting analysis, loss control inspection, and internal committee approval.

Definition — Underwriting Guidelines: A carrier’s internal rules and criteria that define the characteristics of risks the carrier will accept, the rates applicable to each risk class, any conditions or endorsements required, and the underwriter’s authority limits by risk size and type. Underwriting guidelines are proprietary to each carrier and determine the boundaries of the standard admitted market for any given risk type.

Personal Lines Underwriting

Personal lines homeowner’s underwriting in the modern market is primarily automated — the carrier’s systems ingest application data, query third-party data sources, apply scoring models, and produce an accept/decline/rate response, often without human underwriter involvement for standard risks within appetite. Third-party data sources queried at point of sale include: ISO ClaimSearch (prior insurance claims reported by all participating carriers), LexisNexis Risk Solutions (property records, permit history, prior address history), CoreLogic (property characteristics, replacement cost estimate, flood zone, prior claim history), Verisk aerial imagery analytics (roof condition, age, material, skylights, pitch), and FEMA FIRM flood zone from geocoordinates.

Credit-based insurance score (CBIS) is a major underwriting and rating factor in most states for personal lines. The correlation between CBIS and loss frequency is well-established in actuarial research — policyholders with lower CBIS scores file claims more frequently across all personal lines. The mechanism is not fully understood but is thought to reflect underlying characteristics correlated with both financial stress and claim frequency. State regulations on CBIS use vary significantly: California, Massachusetts, Maryland, and Hawaii prohibit its use in property insurance rating; most other states permit it with varying restrictions on transparency and adverse action notice requirements.

Roof condition is now a primary personal lines underwriting factor, driven by the combination of wind and hail claim frequency and the availability of carrier-commissioned aerial imagery analysis. Verisk’s aerial analytics platform analyzes satellite and aerial photography to estimate roof age, material, pitch, and condition score. Carriers use these scores to: decline risks with roofs beyond maximum age thresholds (typically 15–20 years for asphalt shingle); apply roof age surcharges; require certified roof inspections before binding for older roofs; and exclude wind and hail coverage on roofs in poor condition while maintaining the base policy.

Commercial Lines Underwriting

Commercial property underwriting involves more human judgment than personal lines and relies more heavily on direct loss control inspections and submitted COPE data. Commercial underwriters evaluate: the COPE data accuracy and completeness; the insured’s loss history (typically 5 years of loss runs, showing each claim with date, cause, and paid/reserved amounts); the quality of the insured’s risk management program (presence of sprinklers, fire suppression systems, safety training programs, property maintenance standards); the carrier’s existing concentration in the geographic area and building type; and the broker submission quality (complete applications with accurate supporting data produce better pricing and terms than incomplete submissions).

Loss runs — the claim history report from the insured’s current and prior carriers — are mandatory for commercial property underwriting. Carriers typically require 5 years of loss runs, and claims with open reserves attract closer scrutiny than fully closed claims. Underwriters analyze loss frequency (how often claims occur) separately from loss severity (how large claims are when they occur). A risk with high claim frequency but low severity may indicate poor maintenance and poor housekeeping; a risk with low frequency but one catastrophic large loss may be treated differently from one with the same average annual loss spread across many small claims.

Underwriting Categories: Admitted vs. Surplus Lines

When a risk does not meet the underwriting guidelines of admitted carriers (carriers licensed and rate-filed in the state), the broker may place the risk in the surplus lines (non-admitted) market. Surplus lines carriers are not required to use state-filed rates or forms and can write risks that admitted carriers decline — higher hazard occupancies, properties with prior losses, risks in geographic areas where admitted carriers are not writing (coastal Florida, wildfire California, Gulf Coast), and unusual or complex risk structures.

E&S (excess and surplus) market placement comes with differences: surplus lines premiums are typically 30–60% higher than comparable admitted market premiums; surplus lines policies are not backed by state guaranty funds (if the carrier becomes insolvent, policyholders have no guaranty fund recovery); and surplus lines forms may have broader exclusions or different coverage terms than ISO standard forms. The surplus lines market is appropriate for risks that genuinely need it; it is not appropriate for standard risks that could be placed in admitted markets with better preparation of the submission.

Risk Improvement and Underwriting Conditions

Carriers issue risk improvement recommendations (also called loss control orders) as conditions of coverage — requirements that the insured correct identified hazards within a specified time (typically 30–90 days) or face cancellation or exclusion of the uncorrected hazard from coverage. Common conditions on commercial property: roof replacement, electrical system upgrade, sprinkler system installation or impairment repair, removal of combustible storage from hazardous areas, and correction of deferred maintenance visible in the loss control inspection report.

Risk improvements that are completed and documented can produce premium credits of 5–25%. The sprinkler credit — the premium reduction for buildings with operational automatic fire sprinkler systems — is typically 10–40% of the fire portion of the premium, because fire suppression systems dramatically reduce expected fire loss severity. NFPA 13 compliant sprinkler systems in fully sprinklered buildings reduce the probability of a fire exceeding $50,000 in damage by over 80% relative to unsprinklered buildings of similar construction and occupancy, based on NFPA research data.

Frequently Asked Questions