There are two main models that are usually proposed. One is a model that's universal, that just provides a flat income benefit for all people, and then there are adjustments to the taxation system to claw it back. The other would be a negative income tax model—there are different terms for that—where you have a graduated approach. Generally speaking, the research is starting to show that a graduated approach is better at targeting the families that are most in need, but either way it's proposed, it really depends on how it fits in with other systems.
On February 15th, 2017. See this statement in context.