Evidence Based Policy: II. The Promise of ‘Realist Synthesis’

ing away from the particulars of the example, we now have three countercontexts to threaten the long-term efficacy of incentive programmes, namely: • (C1) budgetary constraints • (C2) alternative usage (exchange utility) • (C3) technical limitations on usage (durability etc.) The next task is to put this primitive little theory to work by considering further examples. Before we do so, it is useful to take one step back, in order to see if the negative cases and two additional contexts provide a further nuance for understanding the NRT example. NRT patches are good for nothing else (as far as I am aware!) so exchange (C2) is out of the equation. Durability and technical constraints (C3), however, are real issues in the replacement of nicotine. The withdrawal regime will not work unless it is staged properly and patch dosage carefully regulated downwards. And, in the chewing-gum version, even the mastication techniques (chew and park) need to be perfected (Thompson and Hunter, 1998).