In regard to a wage subsidy, I think that organizations that are delivering wage subsidies would be your first source for stats on how effective it can be. I think where wage subsidy is strong is for clients who wouldn't pass the interview phase in an open competition. Having that training and accommodation bursary and support provides that required incentive, especially for small to medium-sized businesses in retaining people with disabilities.
Right now, I'm not aware of a funding model that asks you to track long-term success, but I would urge that as something to look at when we're looking at sustainable changes so that agencies, employers, and the government have a picture of how people are progressing, and that retention.