PHL-DRG for hospital CFOs, how your payment tier is actually decided

What changes under prospective payment

Under fee for service, you documented what you did and billed for it. Under DRG, you are paid a predetermined amount for the category the case falls into, decided by an automated engine reading your codes.

The consequence for finance is structural. Your revenue per case is no longer a function of resources consumed. It is a function of how accurately the resources consumed were described in code.

How the tier gets set

The primary diagnosis places the case in one of 26 Major Diagnostic Categories. Within that category, secondary diagnoses determine severity, and severity determines the tier.

Secondary codes are graded. A CC marker is a complication or comorbidity. An MCC marker is a major complication or comorbidity and moves the case further up. A case with an MCC can pay several times what the same primary diagnosis pays without one.

Why this creates a documentation problem, not a coding problem

Coders code what they can find. The complications that carry MCC weight, shock, acute respiratory failure, aspiration pneumonitis, are typically recorded in free text narrative by a clinician mid-shift, not entered as structured fields.

So the failure is not that coders are careless. It is that the evidence and the coding sheet live in different formats, and the bridge between them is a tired human reading prose at speed.

Related CC and MCC markers, the codes that set your payment tier

What changes for finance, in one paragraph

Under case rates, revenue per admission was fixed by diagnosis. The finance levers were volume and cost. Under a severity-adjusted system, revenue per admission varies with how completely the record describes what happened. That puts part of your revenue line downstream of clinical documentation.

That dependency is new. Finance now has an interest in a process it has never owned, does not staff, and cannot instruct. Every hard part of this transition follows from that.

Part of your revenue line now sits downstream of a process finance has never owned.

Why the usual levers do not work here

Hiring more coders raises throughput, not tier accuracy. The constraint is not how many claims get coded. It is how much evidence each chart offers to code from, and a faster coder reading the same thin narrative produces the same tier.

Training helps once, then decays. The behavior it targets happens under time pressure, performed by people whose main job is not billing. Anything that depends on somebody remembering a rule at three in the morning has a half life.

Two things do work, and both close the gap between the chart and the claim rather than pushing people to work harder across it. Change what the system asks for at the moment of documentation. Then check the claim against the chart before it goes, rather than after it comes back. Both are process changes rather than effort changes, which is why they hold.

The question to ask your revenue cycle lead this week

Not how many claims were denied. That number is visible, already tracked, and lagging.

Ask instead: of the claims we submitted last month, how many carried fewer than four secondary diagnoses, and of those, how many involved an intensive care admission, a transfer to a higher level of care, or a stay longer than the expected length for that diagnosis.

That intersection is where under-documented severity hides. It is answerable from data you already hold, it takes an afternoon, and it produces a number that is actionable rather than historical.

What hospital finance should be tracking now

Three numbers, none of which most facilities currently produce.

• Case mix index, and whether it is drifting down relative to your actual acuity
• Rate of cases with zero secondary diagnoses coded, which is almost always a documentation artifact rather than a clinical fact
• Tier distribution in your shadow billing output versus what your clinicians would say the tier should be