Revenue leakage is money a practice has already earned - sessions delivered, claims lodged, invoices raised - that never actually arrives in the bank. It is rarely one dramatic loss. The research picture, in Australia and overseas, is of many small, quiet gaps: the session that never got invoiced, the invoice nobody chased, the claim that never came back. Individually they are forgettable. Together they are one of the few ways a busy clinic loses real money without anyone doing anything wrong.
"Leakage" gets used loosely, so it is worth being precise. This is not about charging more, seeing more clients, or marketing harder. It is the gap between the work a practice has already done and the money it has actually collected for that work. Every figure below is from published research or real transaction data, linked at the point it is used.
Clinicians under-bill far more than they over-bill
The public conversation about medical billing is mostly about over-servicing. The data runs the other way. Researchers at the University of Sydney analysed almost 90,000 GP encounters and found undercharging - billing a lower item than the consultation justified, or not billing an item at all - at 11.8% of encounters. Overcharging appeared at just 1.6%.
The study looked at GPs, but the habit it documents is not GP-specific: clinicians err on the side of not charging. In allied health the same instinct shows up as the cancellation fee your own policy allows but nobody raises, the report-writing time that never becomes an invoice line, and the session that simply never gets invoiced because the day got busy.
The invoice you did send gets paid on someone else's schedule
Xero publishes payment-time data drawn from the real invoice and bank-reconciliation records of around 520,000 Australian small businesses - not a survey, actual transactions. In the March quarter of 2026, the average Australian small business waited 24.1 days from issuing an invoice to being paid, and invoices were settled an average of 6.9 days past their due date. And that is the average across every invoice that did get paid - it says nothing about the ones still sitting there.
For a clinic this is where "sent" quietly becomes "stale". An invoice that is a week overdue feels too recent to chase; a month later it feels awkward to chase; six months later nobody remembers to. Third-party payers - insurers, employers, plan managers - stretch this further, because the person who received the care is not the one who owes the money.
Chasing it costs real time - so it often doesn't happen
The reason overdue invoices sit is not mysterious: following up is unpaid admin, and in a small practice the person who would do it is usually also the person answering the phone. In an August 2025 YouGov survey of Australian small and medium businesses commissioned by GoCardless, 63% said they lose money to late payments, and one in five now devotes 6 to 12 working days a year to chasing overdue payments.
A practice facing that trade-off usually makes the sensible short-term call: see the next client, skip the chasing. The cost of that call never shows up anywhere. There is no report in most practice software titled "money you decided not to collect this month".
The claim that goes out and never comes back
Funder billing - Medicare, DVA, WorkCover, health funds, NDIS plan managers - adds a failure mode that patient billing doesn't have: the claim can simply not come back, and nothing alerts anyone. The most striking number here is American, from the Healthcare Financial Management Association, and the mechanism it describes is universal: up to 65% of denied claims are never reworked. Not disputed and lost - never re-attempted at all.
The pattern is easy to picture in an Australian clinic. A claim is lodged, it bounces on a technicality - a lapsed referral, a wrong item number, an expired care plan - and the rejection lands in a portal nobody checks daily. The session was delivered. The money was real. The only thing between the practice and payment is someone noticing, and noticing is nobody's job.
Funded care that never gets used
There is one more gap worth naming, and it is not money owed - it is care that was approved and never delivered. The Australian Institute of Health and Welfare looked at patients whose GP had set up a Team Care Arrangement, the mechanism that funds Medicare-subsidised allied health sessions. Of the roughly 870,000 patients who had a TCA coordination service in 2019, 35% went on to claim none of their allied health sessions at all.
Some of that is patient choice, and some of it is recovery - not every gap is a problem. But a patient who stopped three sessions into a funded plan of ten is first a clinical outcome and only second a business one. For the practice, it is also the least visible gap of all: nothing is overdue, nothing is unpaid, there is simply a referral or care plan quietly expiring with sessions still on it.
Why none of this shows up
Look at the shape these gaps share. Each one is individually small. Each one is invisible in the screens a practice actually looks at day to day - the calendar and today's client list. And each one is nobody's job to find. The data to find every single one of them already sits inside the practice management system; what's missing is anything that cross-checks it. Appointments live in one report, invoices in another, payments in a third, referrals in a fourth, and leakage lives precisely in the joins between them.
None of this is incompetence. It is what happens when collecting money is a side task of people whose actual job is care.
What a practice can do about it
The manual version is a monthly ritual, and practices that do it consistently do recover money:
- Run an uninvoiced appointments report - completed sessions with no invoice attached.
- Run aged receivables and chase everything older than your own payment terms.
- Reconcile lodged claims against remittances, and rework anything that bounced.
- Review referrals, care plans and session packs for unused sessions nearing expiry.
The honest weakness of the ritual is the same one the research keeps pointing at: it depends on somebody doing it, every month, on top of their actual job. That is the gap we built RIFT to close. It reads the billing side of your Zanda or Cliniko data, runs exactly those cross-checks continuously, and chases what it finds - so the uninvoiced session surfaces in the week it happened, not at the end of a quarter when somebody finally runs the report.