[darren0]

"With 4 out of 5 people keeping their flats, “Housing First” is effective in the long run. In 20 percent of the cases, people move out because they prefer to stay with friends or relatives – or because they don’t manage to pay the rent. But even in this case they are not dropped. They can apply again for an apartment and are supported again if they wish."

There are no preconditions, but there are conditions to maintain. In this case, rent being required apparently. This is the recipe for success that I've seen. And if they don't maintain the conditions they get kicked out with the opportunity to come back and try again.

[slothtrop]

Since homelessness is mostly transient in general, I'm skeptical of the claim to effectiveness, since it's likely that a large portion of a sample would move on within a year anyway.