HealthCare.gov, the US federal website for buying health insurance, run by the Centers for Medicare & Medicaid Services (CMS), launched on 1 October 2013.
CMS knew the build was behind. By August it was clear the system would not be fully tested before launch; as one contractor put it, "You can't test what is not built." CMS never completed full end-to-end testing, the run that checks the pieces work together, because the pieces arrived too late. Yet no one in CMS leadership seriously discussed delaying the date. Some staff wrongly believed the law set it; the law only required coverage to begin by 1 January 2014.
On launch day, 250,000 people were on the site at once: five times the simultaneous users expected, the US Chief Technology Officer said. Outages began within 2 hours.
Volume wasn't the only problem. The first bottleneck was EIDM, the system for creating accounts and checking identity. Every visitor had to go through it, and its contractor said later it hadn't known that, so it underestimated the capacity needed. A CMS official called it "a small, one-lane onramp to a major highway." Behind it sat bigger coding problems the team couldn't even see until the onramp was fixed.
Only six consumers managed to submit an application and select a plan on the first day.
By 1 December 2013, CMS, contractors and outside experts had the site handling more than 35,000 concurrent users without crashing. The first enrollment period still ended with 5.4 million people having selected a plan.
- 250,000 concurrent users on launch day, about five times what was expected
- 6 consumers applied and selected a plan on day one
- 42 % of the time working in early November 2013, over 90 % by the end of the month
- 5.4 million people selected a plan in the first enrollment period
Why it matters: Testing the pieces is not testing the system. Test end to end before launch, and size the one component every user must pass through for all of them.