When Trump cut CSR payments, states' 'silver loading' made gold plans cheaper
Insurers raised only silver premiums — the subsidy benchmark — so tax credits ballooned and many enrollees' 2018 plans got cheaper.
Read the casegenius.wikiA CASESTUDIES.CHAT ARCHIVE
Good problems.
Brilliant solutions.
Ingenious ideas that solved difficult problems. Explore what made them work.
The full archive, in the appThe latest cases
300 RECENT CASES · REGULARLY UPDATEDSanta Fe's steep water tiers cut use 20% per person while population grew 10%
$6.06 per thousand gallons up to 7,000, then $21.72 — the costliest water in America cut per-capita use from 162 to 96 gallons a day.
Read the caseRush's 'time tax': a 25-second wait steers vending users to healthier snacks
A device holds junk-food vending snacks for 25 seconds while healthy ones drop instantly — a 'time tax' that matched a 25-cent discount without denting revenue.
Read the caseMedicare's Pioneer ACO bet hospitals a share of savings — it saved $384M in 2 years
Thirty-two systems kept 70% of savings if they beat cost targets and repaid overruns — the first Obamacare experiment certified to save money.
Read the caseCalifornia's groundwater cops skipped meters — Land IQ measures water use from orbit
Satellite imagery turns every field into a readable water bill: crop fingerprints plus evapotranspiration now police a dozen-plus agencies' quotas.
Read the casePainted eyes on 683 cows, zero lion kills — the eyespot trick that broke ambushes
Botswana herds with eyes painted on their rumps lost no cows to ambush predators in four years, while unmarked and cross-marked herds did.
Read the caseCorsi-Rosenthal Box: $70 of box fan and furnace filters beats costly HEPA purifiers
An engineering dean's Twitter idea and a filter maker's build: four MERV-13 filters plus a box fan clean classroom air for $70 and 20 minutes of duct tape.
Read the caseShame instead of subsidies: CLTS helped take Nepal from 10% to 70% toilets
Guided village walks that find and confront open defecation replaced toilet giveaways — and toilets people choose to build actually get used.
Read the caseBoston Medical Center prescribed electricity — rooftop solar pays patients' bills
Half the hospital's 519 rooftop panels are turned into ~$50 monthly utility credits for 80 medically vulnerable patients who can't afford power.
Read the caseWindows 95 special-cased SimCity's freed-memory bug instead of telling Maxis to fix it
Microsoft detected SimCity by name and ran an allocator that delayed freeing memory — plus version lies and per-app fixes — to remove reasons not to upgrade.
Read the caseWhen blackout warnings hit, Britain paid households to cut peak-time power use
Instead of rolling blackouts, the grid paid smart-meter homes £3–6 per saved kWh in notified peak windows — Octopus expected about £100 a household over winter.
Read the caseNHS handed Covid patients £20 oximeters — and triaged them by number, not feeling
Covid Oximetry@home gave ~300,000 pulse oximeters to high-risk patients in England; readings three times a day against two thresholds caught silent hypoxia.
Read the caseBaltimore civic hackers freed bus data MTA priced at $600K — it was already streaming
Chris Whong read the AJAX calls of the MTA's own bus-tracker web app, found the “too expensive” GTFS data already flowing, and republished it for free.
Read the caseHamilton priced premium seats off the scalpers' own resale data, at $849 a ticket
Instead of fighting ticket bots, Hamilton's producers read StubHub and SeatGeek as a live price survey and raised face value to the secondary-market average.
Read the caseDarkSide ran ransomware like a franchise — tiered cuts, affiliates, a helpdesk (interview)
NYT reporter Michael Schwirtz got inside DarkSide’s communications: affiliates on a sliding commission, a Bitcoin helpdesk for victims, M+ in a year.
Read the caseBaochip-1x got fabbed on Crossbar's wafer and shipped in 27,000 DEF CON badge tokens
An independent hacker piggybacked his open-source secure chip on another company’s paid wafer run, then bootstrapped distribution through conference badges.
Read the caseUPS gave sorters $8 Bluetooth headsets and trucks beacons that beep at wrong boxes
UPS's EDGE program turned facility data into one-word voice directions, misload alarms and shift forecasts, worth $200–300M a year.
Read the caseKeySweeper hid a $10 wireless keyboard sniffer inside a working USB charger
Samy Kamkar's Arduino-based charger sniffed, decrypted and uploaded every keystroke from Microsoft wireless keyboards — and looked like a phone charger.
Read the caseGoSecure recorded hackers' own screens for three years inside an RDP honeypot
A deliberately weak RDP machine let GoSecure capture 2,300 attacker sessions on video — tools, habits, even personal email logins.
Read the caseDelta replaced gut-feel fare agents with software and priced every seat by data
After deregulation, Bob Cross studied the 50 agents setting fares by intuition and replaced them with revenue-management software — Delta returned to profit.
Read the case