Synthetic · supply-side wedge · jeffpinto.com
Set a $/hr peak-window incentive. Watch the courier-utilisation curve shift, and watch the lift decompose into the couriers you actually bought versus the free riders who'd have shown up anyway. A marketplace launch is a supply-elasticity problem wearing a growth-story costume.
38% of the lift is free riders at this incentive. Spend rises faster than incremental trips — that’s the diminishing-returns tax finance eventually asks about.
Left axis: utilisation vs incentive (saturating). Bar at the chosen incentive splits the lift green (incremental) over amber (free-rider).
The demand side gets the press release; the supply side gets the late-night Slack thread when the Tuesday courier fill-rate drops below the merchant SLA. The free-rider column is the one most experimental-design write-ups skip — it tells you whether the incentive is buying behaviour or buying a payroll bump for people already on the road.
Python core: courier_elasticity.py · cohort_decay.py