Maybe 100 people. Likely currently unemployed and poor.  So we call that means-tested welfare, not a universal basic income.  And the control group sure won’t have any response bias, for sure.

Tubbs says he hopes the experiment will run at least three years and benefit at least 100 people, which would put the total cost of the transfers at $1.8 million (before implementation costs). If it works, he envisions a public-private partnership eventually expanding the approach to cover more of the city.That would probably require significant outside funding. The fiscal situation in Stockton is much improved from when it fell into bankruptcy, but a truly universal, not-lotteried benefit at the municipal level would be challenging to enact. The plan would likely trigger an influx of residents from nearby towns (and maybe even some from farther away). The town, facing high borrowing costs due to its junk bond-level credit ratings post-bankruptcy, would need to raise taxes in response to that. Higher taxes could in turn lead some high-income residents to leave, setting off a vicious cycle.  Tubbs concedes that ideally this is the kind of policy that would be implemented at the state or national level. Nonetheless, he says, “It’s a great opportunity to have this conversation about all these factors. … Stockton is a proxy for America: its diversity, its people. It’s a place that’s emerging and has big bold ideas.”

Source: 3 years ago, Stockton, California, was bankrupt. Now it’s trying out a basic income. – Vox