At the time they were set up, there was some research showing that x percent more gave up if they were nicotinised to the eyeballs for 12 weeks.
Since then its been shown that a lot more would give up if offered more open ended support, but that would need open-ended funding, as daktari suggests.
i've been doing the NRT programme for the past 4 years. in that period i think only a couple of people have actually given up!!! the rest come back wanting to give up again and again!!! something personal comes up and they start smoking and end up feeling guilty after sometime and are determined to stop. the cycle continues...........