Why insurers deny claims, and which denials are worth fighting

Denials are now routine, not exceptional

The initial denial rate on medical claims rose to 11.81% in 2024, according to Kodiak Solutions, drawing on data from more than 2,100 hospitals and 300,000 physicians. Premier's national provider survey put private payer denial rates near 15%, reaching as high as 49% in individual cases.

Roughly one claim in eight to one in seven comes back. Any billing process that treats a denial as an unusual event is mis-designed for the volume it will actually receive.

The number that decides whether to fight

Kodiak's analysis contains the single most useful fact in this whole subject: payers ultimately pay approximately 90% of the claims they initially deny. Their conclusion was that initial denials function substantially as a way of slowing payment rather than refusing it.

If nine in ten denied claims are payable, the question is never really "is this worth appealing". It is "do we have anyone with the hours to appeal it". Practices do not lose this money because they lose arguments with payers. They lose it because nobody works the queue and the balance ages out.

What it costs to fight one

Premier found the administrative cost of fighting a single denied claim rose from $43.84 in 2022 to $57.23 in 2023. Denied claims went through an average of three rounds of review with insurers, each cycle taking between 45 and 60 days.

Three rounds at 45 to 60 days is four and a half to six months of elapsed time on a single account. That is why denial work has to be a standing job rather than a project — a queue worked in bursts every few months will always have accounts falling out of timely filing between bursts.

It is also why the arithmetic favours prevention heavily. At roughly $57 of administrative cost per denial, an eligibility check that prevents one is cheaper than the appeal that recovers it, and it recovers the money months earlier.

The categories worth separating

Denials are not one pile. Eligibility and registration denials are almost entirely preventable and should be measured as a front-desk metric rather than a billing one. Authorisation denials are preventable but need somebody chasing payers before the visit. Coding denials need a coder, not a caller. Medical necessity denials need clinical documentation and often a physician's time. Timely filing denials are unrecoverable and are the only category where the right response is to fix the process and move on.

Sorting the ageing report into those five buckets is usually the highest-value hour anybody spends on it, because it tells you which one is actually costing you and therefore who needs to be doing what.

What good looks like

Every denial categorised by reason, worked to a closing outcome rather than a touch, with the payer reference number and the name of the person spoken to written down. The categorisation is what stops the same denial recurring next month; the reference number is what makes the second call shorter than the first.