Process

Workers’ Compensation Premium Calculation Process

Workers’ Compensation premiums are calculated using a structured, step-by-step hierarchy. The process starts with payroll exposures and applies various risk-adjusted modifiers, discounts, and fees.

Core Pricing Components

• Payroll (Exposures): The primary exposure base, typically measured in units of $100.
• Classification Codes: Identifiers assigned to different occupational categories based on their risk level (e.g., roofing vs. clerical office work).
• Manual Rate: The rate charged per $100 of payroll, determined by the risk classification and state jurisdiction.
• Experience Modification Factor (E-Mod): A rating factor based on the employer’s historical loss experience compared to similar employers in the same class.
  • $\text{E-Mod} > 1.0$: Indicates worse-than-average loss experience (resulting in a surcharge).
  • $\text{E-Mod} < 1.0$: Indicates better-than-average loss experience (resulting in a credit/discount).

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Step-by-Step Premium Hierarchy

The calculation flows sequentially from manual rate application to the final guaranteed cost premium:

graph TD
    A[Payroll & Manual Rate] -->|Step 1| B(Manual Premium)
    B -->|Step 2: Experience Mod| C(Modified Premium)
    C -->|Step 3: Schedule Mod| D(Standard Premium)
    D -->|Step 4: Premium Discount| E(Discounted Premium)
    E -->|Step 5: Add Expense Constant| F(Calculated Premium)
    F -->|Step 6: Apply Minimum Premium| G(Guaranteed Cost Premium)

1. Manual Premium

Calculated for each combination of location and job classification:

$$\text{Manual Premium} = \sum \left( \text{Manual Rate} \times \frac{\text{Payroll}}{100} \right)$$

2. Modified Premium

Applies experience rating to qualified risks (see Experience Rating):

$$\text{Modified Premium} = \text{Manual Premium} \times \text{Experience Modification Factor (E-Mod)}$$

3. Standard Premium

Applies schedule rating (adjustments for specific risk characteristics like safety programs or superior facilities, see Schedule Rating):

$$\text{Standard Premium} = \text{Modified Premium} \times \text{Schedule Modification Factor}$$

(Note: Round intermediate calculation to the nearest penny).

4. Apply Premium Discount

Larger policies receive premium discounts to reflect economies of scale in expenses (see Premium Discount):

$$\text{Discounted Premium} = \text{Standard Premium} - \text{Premium Discount}$$

(Note: The premium discount is typically calculated using a multi-tiered table and rounded up to the nearest dollar).

5. Add Expense Fee / Constant

Add the flat expense constant (fee) to cover basic policy administrative costs (see Expense Fee):

$$\text{Subtotal Premium} = \text{Discounted Premium} + \text{Expense Fee}$$

6. Guaranteed Cost Premium (Final)

The final premium is subject to a minimum premium limit to ensure administrative and basic exposure costs are covered:

$$\text{Guaranteed Cost Premium} = \max(\text{Subtotal Premium}, \text{Minimum Premium})$$

[!IMPORTANT] Always verify the order of operations: Experience Rating (E-Mod) is applied before Schedule Rating. The minimum premium acts as a floor ($\max$ function), not a ceiling.