What Is an X-Mod and How to Lower Yours

Quick Answer

Your Experience Modifier (X-Mod) is a multiplier the WCIRB California assigns to your workers' comp policy based on three years of claims history. A 1.00 is the industry average for your class. Below 1.00 is a discount; above 1.00 is a surcharge. A 0.85 X-Mod cuts your WC premium 15%; a 1.25 X-Mod adds 25%. Lowering your X-Mod is the single highest-leverage way to cut WC cost. Call (858) 925-9555 for a free X-Mod review.

How the X-Mod Is Calculated

The WCIRB uses your three most recent complete policy years (not the current one) — typically years 1–3 prior. The formula compares your actual paid losses against the expected losses for your class code at your payroll level. The result is published on your Experience Rating Form, which the WCIRB sends 60+ days before each renewal.

Why It Matters

X-Mod	Effect on premium
0.75	25% discount
0.85	15% discount
1.00	Industry average — no adjustment
1.15	15% surcharge
1.40	40% surcharge

A contractor with $300K payroll at the Class 5183 plumbing rate of $6.75/$100 has $20,250 base premium. At 1.40 X-Mod that becomes $28,350. An $8,100 difference on one number.

How to Lower It

1. Close open claims fast. A claim sits at "reserved value" until closed — even if you'll never pay that much. Push claims adjusters to close.
2. Return injured workers to light duty. Days off pay out lost-time benefits. A modified-duty job keeps the claim small.
3. Investigate every claim aggressively. Reject fraudulent or non-work claims early.
4. Implement a safety program. Lower injury frequency improves your loss ratio.
5. Separate clerical payroll from field payroll — clerical sits in Class 8810 at $0.30/$100 vs field rates much higher.
6. Don't suppress claims — failing to report a real claim and having it surface later is far worse for your X-Mod than reporting promptly.

What Triggers a High X-Mod

• A single severe claim (back injury, fall, long-term disability)
• Pattern of small frequent claims
• Slow claim closure (reserves stay high for years)
• Misclassification (claims in wrong code skew your ratio)

Related: Workers' Comp Cost · How to Lower Workers' Comp Premium · Workers' Compensation