The free routes come first, and a good advocate will tell you so. CMS's own guidance on finding a patient advocate lists, in order: an online search for an advocacy group covering your state or your condition; your hospital's own patient advocate, who CMS says can help you "understand your bill", "apply for financial assistance" and "access medical records"; the Patient Advocate Foundation, a nonprofit; and, for veterans, the VA's patient advocacy program. CMS also runs a No Surprises Help Desk on 1-800-985-3059. None of that costs anything.
On top of those, federal law gives an insured patient two procedural rights that a billing advocate is often simply exercising. 45 CFR 147.136 requires non-grandfathered group health plans and issuers to run an internal claims and appeals process and to provide an external review, either through an applicable state process under paragraph (c) or through the federal process at paragraph (d). A patient can use both without hiring anyone. The value a paid advocate adds is time, persistence and pattern recognition, not access to a process otherwise closed.
The two fee structures are not equivalent, and the difference is not the rate. An hourly engagement prices the advocate's time, so the cost is knowable in advance if the scope is capped, and it is payable whether or not the bill comes down. A contingency engagement prices a share of the reduction, so the advocate is paid only on a result, and the buyer's exposure scales with the size of the bill rather than with the difficulty of the work.
The question that decides whether a contingency is fair is the denominator. "Savings" can mean the reduction from the hospital's gross charge, the reduction from the amount the patient was actually being asked to pay, or the reduction from the amount the patient would have owed anyway once the plan finished processing and any automatic self-pay discount was applied. Those are very different numbers. A hospital's published discounted cash price and its financial assistance policy exist independently of the advocate, so a fee computed off the list charge can capture a discount the patient was entitled to before anyone was hired. Getting that definition written into the engagement, in dollars, is the single most useful thing a buyer can do.
A second structural point about contingency pricing: the fee scales with the size of the reduction rather than with the strength of the argument, so the arrangement rewards attacking the largest line rather than the line most likely to be wrong. That is a fact about the incentive, not an accusation about any particular advocate, and the practical answer is to ask what the advocate intends to challenge and why before agreeing to the fee.
CMS's warning is specific and worth quoting as written. Its guidance says: "Don't pay a person or a service who promises to keep medical bills off your credit report or to protect you from unexpected out-of-network medical costs. Steer clear of people who want to charge you an upfront fee for resolving your debt and credit situation." Both halves are promises about outcomes that are set by law and by contract rather than by advocacy, which is why an offer to deliver them is a signal in itself.
Where the work genuinely pays. The cases with the most room in them share a shape: a large facility bill with many lines and therefore many chances of a quantity or duplication error; an out-of-network dispute where the applicable protections and the correct cost-sharing calculation are contested; a denial that turns on coding rather than on medical judgment; and a self-pay balance where the patient is being billed off list charges and has not been screened for the hospital's financial assistance policy. The cases with the least room are the mirror image: a small bill, a bill already priced at the plan's allowed amount with the correct cost sharing applied, or a denial that turns on a coverage exclusion the plan document states plainly.
