If you’ve ever read through a workers compensation policy and felt like you needed a law degree to understand it, you’re not alone.
Workers comp comes with its own language — terms that insurance companies and adjusters use every day that most business owners have never heard until something goes wrong. This glossary breaks down the 15 most important terms you’re likely to encounter as an Oklahoma employer, in plain English, so you know exactly what you’re dealing with before you need to know it.
1. Workers Compensation Insurance
Let’s start at the beginning.
Workers compensation insurance — commonly called workers comp — is a type of business insurance that covers medical treatment and a portion of lost wages when one of your employees is injured or becomes ill because of their job. In Oklahoma, if you have one or more non-family employees, you’re almost certainly required by law to carry it under Title 85A of the Oklahoma Statutes.
Think of it as a two-sided safety net. Your employee gets medical care and income replacement while they recover. You get protection from the kind of personal financial liability that could otherwise put you out of business.
2. Premium
Your premium is the amount you pay for your workers comp coverage — either monthly, quarterly, or annually depending on your policy structure.
Workers comp premiums aren’t a flat fee. They’re calculated based on three things: your total payroll, the class codes assigned to your employees’ job types, and your Experience Modification Rate. All three of those numbers together determine what you pay. Change any one of them and your premium moves.
3. Class Code
Every job type in America is assigned a four-digit classification code based on the level of risk involved in that work. An office administrator has a low-risk code. A roofing crew member has a high-risk code. The riskier the work, the higher the rate associated with that code — and the more you pay per $100 of payroll for those employees.
Getting your class codes right matters enormously. Wrong codes mean you’re either paying more than you should or you’re underinsured. Both are problems. We review class codes for every client we work with before renewal because this is one of the most common and most fixable sources of overpayment in Oklahoma.
4. Experience Modification Rate (EMR)
Your Experience Modification Rate — also called your experience mod, mod rate, or just EMR — is a number that reflects your company’s claims history compared to other businesses of similar size and type in your industry.
An EMR of 1.0 is average. Below 1.0 means you’ve had fewer or less costly claims than expected — and you pay less than the standard rate. Above 1.0 means your claims history is worse than average — and you pay a surcharge on top of the standard rate.
Your EMR is recalculated every year using the three most recent policy years. A single serious claim can move it significantly — and that impact follows your business for years.
5. Medical-Only Claim
A medical-only claim is one where the injured employee receives medical treatment — an ER visit, a few doctor appointments, some physical therapy — and returns to work without missing any significant time.
Medical-only claims still affect your EMR, but most rating formulas discount them at roughly 70%, meaning they count for less than their full dollar value. The system is designed to encourage employers to seek prompt care for minor injuries without being disproportionately punished for doing so.
6. Lost-Time Claim
A lost-time claim — also called an indemnity claim — is one where the injury is serious enough that the employee misses work beyond a short waiting period. In Oklahoma, that waiting period is typically three days. Once that threshold is crossed, the employee becomes entitled to wage replacement benefits in addition to medical treatment.
Lost-time claims carry significantly more weight in your EMR calculation than medical-only claims. A single lost-time claim can do more damage to your mod rate than several medical-only claims combined. This is why actively managing return to work — even through modified duty — is one of the most financially important things you can do after a workplace injury.
7. Indemnity Benefits
Indemnity benefits are the wage replacement payments made to an injured employee who is unable to work due to a work-related injury or illness.
In Oklahoma, indemnity benefits are typically calculated at approximately 70% of the employee’s average weekly wage, subject to state minimums and maximums that are adjusted periodically. There are different types of indemnity benefits depending on the nature and permanence of the disability — temporary total disability, temporary partial disability, permanent partial disability, and permanent total disability — each with its own calculation and duration rules.
8. Claims Adjuster
A claims adjuster is the person assigned by your insurance carrier to investigate, manage, and settle a workers comp claim. They review the circumstances of the injury, determine whether the claim is covered under your policy, authorize medical treatment, manage benefit payments, and communicate with everyone involved in the claim.
One thing to understand clearly: the claims adjuster works for the insurance carrier — not for you and not for the injured employee. Their job is to manage the claim fairly and within the terms of the policy. Having an independent agent in your corner means you have someone who specifically advocates for your interests throughout the process.
9. Return-to-Work Program
A return-to-work program is a structured plan for getting an injured employee back on the job as quickly and safely as possible — even if they can’t immediately return to their full regular duties.
This often involves modified or light duty work that accommodates the employee’s medical restrictions during recovery. A desk-based role for someone who normally works outdoors. Reduced hours for someone who’s still healing. The goal is to keep the employee engaged and productive while reducing the financial impact of the claim.
From a premium standpoint, a well-executed return-to-work program is one of the most effective tools available for controlling your EMR. Every week an employee spends on lost-time benefits is a week that claim is growing in weight and cost.
10. Certificate of Insurance (COI)
A Certificate of Insurance is a document that proves an individual or company carries active insurance coverage. In the workers comp context, the COIs you need to worry about are those belonging to the subcontractors you hire.
If a subcontractor doesn’t carry their own workers comp coverage and gets injured while working for you, your carrier may consider them your employee — which means their injury becomes your claim and their payroll gets added to yours at audit time.
Collecting and keeping current COIs from every subcontractor you hire is not optional. It’s one of the most basic and most commonly neglected risk management practices we see among small business owners in Oklahoma.
11. Audit
Workers comp policies are audited at the end of each policy period — usually annually. During an audit, your insurance carrier reviews your actual payroll records for the year and compares them to the payroll estimate used to calculate your original premium.
If your actual payroll was higher than estimated, you’ll owe additional premium. If it was lower, you’ll receive a refund or credit. Audits can also reveal classification issues — employees doing work that doesn’t match the codes they were assigned — which can result in additional charges.
The best way to handle an audit is to be prepared. Accurate records, properly documented subcontractor COIs, and correctly classified employees make audits straightforward. Mess any of those up and the audit becomes expensive and stressful. Eagle National sits in on audits with our clients — we know what auditors look for and we make sure the process is as smooth as possible.
12. Subrogation
Subrogation is the process by which your insurance carrier — after paying out a workers comp claim on your behalf — pursues reimbursement from a third party who may have been responsible for the injury.
Here’s an example. One of your employees is injured in a car accident while making a work-related delivery. Another driver caused the accident. Workers comp pays for your employee’s medical care and lost wages. Your carrier then has the legal right to pursue the at-fault driver’s insurance company to recover those costs.
You don’t manage this process — your carrier does. But it’s worth knowing it exists because a successful subrogation recovery can reduce the financial impact of a claim on your future premiums.
13. Maximum Medical Improvement (MMI)
Maximum Medical Improvement — often abbreviated MMI — is the point at which a treating physician determines that an injured employee’s condition has stabilized and is unlikely to improve further with additional treatment.
MMI doesn’t necessarily mean the employee is fully recovered. It means they’ve reached the best level of recovery that medical care is expected to achieve. Once MMI is declared, the nature of the claim shifts — temporary benefits typically stop, and the focus moves to evaluating any permanent impairment and resolving the claim.
MMI is a significant milestone in any lost-time claim. Understanding where it sits in the process helps you anticipate the timeline and next steps.
14. Exclusive Remedy
Exclusive remedy is one of the foundational principles of workers compensation law — and one of the most valuable protections it provides to employers.
Under the exclusive remedy doctrine, an employee who is injured on the job generally cannot sue their employer in civil court for damages. Instead, workers comp is their exclusive — their only — legal remedy. In exchange for that protection, the employer agrees to carry workers comp insurance and provide benefits regardless of who was at fault for the injury.
This is a big deal. Without workers comp, a single workplace injury could expose you to an unlimited civil lawsuit. With proper workers comp coverage in place, your liability is defined and contained within the policy.
15. Experience Period
Your experience period is the window of time that your EMR calculation looks back at to assess your claims history. In Oklahoma — as in most states — the experience period covers the three most recent completed policy years, not counting the current year.
So if your policy renews in January 2026, your EMR is based on claims from 2022, 2023, and 2024. A bad claim from 2021 has already rolled off. A bad claim from 2024 is still very much in the picture.
Understanding your experience period helps you know exactly how long the impact of a specific claim will affect your premium — and when it will finally drop off your record.
A Final Word From Eagle National
These 15 terms are the ones we talk through with our clients most often — the ones that come up when a claim is filed, when a renewal lands on your desk, or when an audit shows up unannounced.
Knowing this language doesn’t make you an insurance expert. But it does mean you’ll never sit across from an adjuster or an auditor feeling like you’re in over your head.
If you have questions about any of these terms as they apply to your specific policy — or if you just want a second set of eyes on your coverage before your next renewal — give us a call. The conversation is free and it takes about 15 minutes.
Eagle National Insurance Group Tulsa, Oklahoma (918) 213-4443 enatinsurance.com
Eagle National Insurance Group is an independent insurance agency serving small businesses across Oklahoma. We specialize in commercial insurance including workers compensation, general liability, and business owner policies.