What the model says, in one line
Roopa buys engagement. Engagement buys adherence. Adherence buys two different things that pay in two different currencies: a clinical outcome for the patient, and a return visit for the clinic. Everything below is that chain, made arithmetic.
The four gauges
Like a car: two you watch every week because they move, two you check monthly because they lag.
Inputs
1 · Engagement (what Roopa controls)
Without any support, published behaviour-change work looks like A∞ ≈ 0.15–0.25 and τ ≈ 2–3. Roopa's entire product thesis is: raise A∞, stretch τ. If it can't move these two numbers, nothing downstream happens.
2 · Dose → outcome (biology)
Anchor: a fully adherent 12 weeks should produce roughly 5 % weight loss, so kW ≈ 0.42. You do not get to estimate these from 10 patients. Take them from the PCOS lifestyle literature, then check your patients aren't wildly off.
3 · Clinic economics (who pays)
β is the number the whole business rests on and the one you have no data for. Everything else you can look up or ask ops.
Adherence over time
The exponential decay curve. The shaded area is the dose — the thing that actually produces an outcome. Two curves: with Roopa (your sliders) and the no-support baseline.
The chain, computed
Patient side
Clinic side
Doctor time — the constraint that kills pilots
Time per primary doctor per patient per week. The library hit rate h is what Roopa is really selling to the doctor.
Result
Target ≤ 5 min/patient/week. Above that, doctors stop opening the digest and the whole loop dies quietly.
What you can and cannot learn from 10 patients
Estimable at n = 10
| A₀, A∞, τ | yes — 12 weekly points per patient |
| h (library hit rate) | yes — every question is logged |
| q, tr, doctor minutes | yes |
| c (cost per patient) | yes |
| p₀ (baseline return rate) | from IDEA's records, not the pilot |
Not estimable at n = 10
| kW, kH — dose→outcome | needs hundreds; borrow from literature |
| β — adherence→return | needs a control arm; the honest pilot output is a range |
| Anything about cycles regularising | too few events in 12 weeks |
So the pilot's job is not to prove the outcome. It is to prove the left half of the chain — that engagement holds and doctor time stays small — and to measure p₀ so the revenue case can be argued.
How to read this honestly
Every number here except your own operating costs is currently a guess. The model's value is not the output — it is that it tells you which guess to attack first. Rank the sliders by how much the break-even moves when you nudge them: that ordering is your research agenda. Right now it is almost certainly β, then A∞, then p₀.