DDx — DIFFERENTIAL INDEX
Why growth stalls: the same complaint has several different causes
BEFORE YOU BRIEF ANYBODY
How to use this before you brief an agency
A differential is the list of things that could be producing what you are seeing, ranked by how likely each one is, with the finding that tells them apart. "Growth has stalled" is a presentation, not a diagnosis — and the four or five conditions that produce it are treated completely differently. Getting that wrong is how a practice spends a year fixing the wrong thing.
Five presentations, worked through for twelve group types. 284 causes and 284 tests, each cited to a primary source. Nothing here describes an engagement or a client — it is reasoning, not a case record.
The tests are written so you can run them yourself. If one of them tells you the problem is not a marketing problem, that is the correct answer and it costs you nothing.
BY PRESENTATION
Patient acquisition cost is climbing
The most common presentation and the most frequently misdiagnosed, because at least two of its causes are not cost increases at all. Auction prices did rise, and there is a court finding behind part of that. But the same symptom is produced by a conversion loss further down the funnel priced as media, by a mix shift toward a more expensive service line, by re-buying patients you failed to retain, and — often — by a measurement error in which the denominator changed and nobody noticed. The tests that separate them run on your own data.
New patient volume is short of plan
The phone rings, the forms arrive, the referral relationships look intact, and the number at the end of the month is under target. Volume shortfalls come from a demand shortage, a capture failure, a capacity ceiling that is quietly rejecting demand, or a plan built on an assumption nobody re-tested. These are treated completely differently, and the cheapest of them costs no media at all.
Growth has plateaued
Production is flat against last year while the marketing invoice holds or rises. The plateau is the hardest presentation to diagnose because it is the one most likely to be structural: a full schedule, a saturated catchment, a collections gap, or a business already at the top of its own segment's distribution and mistaking the ceiling for a failure.
Performance varies by location
Same name, same playbook, same spend per site — and the sites do not behave alike. In most groups the spread between best and worst site is larger than the group's own year-over-year change, which makes this the highest-value presentation on the list and the one that pooled reporting is structurally incapable of showing.
Preparing for sale
The last two years look strong and a banker has been in the building. The question is whether a buyer reads the growth as repeatable or as a good run — and the answer usually lives in the founder's head, in relationships held personally, and in numbers that were never defined consistently enough to be re-run by somebody else.
BY GROUP TYPE
Twelve group types, five presentations each
DSO & general dentistry
Specialty dental
Veterinary groups
Dermatology groups
Behavioral health
Urgent care
Multi-specialty MSO
Eye care groups
PE platforms & rollups
Med spa & aesthetics
Orthopedic & MSK
Fertility networks
WHICH ONE
How to tell which one you have
Start from what you can see rather than from what you suspect. If the number that moved is cost, read the acquisition-cost page. If the number that moved is volume, read the volume page. If nothing moved at all, read the plateau page. If the group total looks acceptable and you have a nagging feeling it is hiding something, go straight to the variance page and read your sites separately — that is the one most likely to change what you do next week.
Then run the tests rather than accepting the description. Every cause on every page carries a measurement you can perform in your own systems, with the finding that confirms it and the finding that rules it out. Two or three usually apply at once; the ranking on each page is by likelihood, not by certainty.
If the tests tell you this is not a marketing problem, that is the correct answer and it cost you nothing. It is also the answer we would have given after six weeks, which is why the tests are published rather than sold.
HOW THIS FITS
| BENCHMARKS → | Where you stand. Median, quartile and top-decile reference ranges by specialty. |
| DIFFERENTIALS | What is likely wrong, how to tell the causes apart, and what resolves each. |
| PROGNOSIS → | What determines how it will go, before anyone does anything. |
| SOURCES → | How we know any of it — and which sources we refuse to use. |
A differential narrows the list. It does not close it — that is what the examination is for.
APPLY — 6 / QUARTER →