Regarding evidence based policy making, the episode of the Isles Report is interesting.
Adams writes:
However within the Department of Transport, the promoters of the seat belt bill, my study had raised concerns. The Department commissioned a critique of my report by J E Isles. His report examined evidence from eight European countries (a subset of the 18 examined in my report) that had passed seat belt laws. He concluded that a law making the wearing of seat belts compulsory “has not led to a detectable change in road death rates”. For promoters of the bill this was an inconvenient truth. The Isles report was dated April 1981, more than three months before the parliamentary debate that led to the passage of the legislation. But it was suppressed. It was not published, and was not allowed to inform that debate. The Isles Report did not see the light of day until its existence was disclosed by New Scientist in an article published on 7 February 1985 – more than three years too late.
In the 1981 Parliamentary debate opponents of the law described my report variously as “bogus”, “riddled with inaccuracies”, “eccentric”, “preposterous”, “spurious”, and “wrong”. One supporter of the law (Austin Mitchell MP) described my report as “the only one that the hon. and learned Gentleman [Ivan Lawrence MP] can dredge up.” The Secretary of State for Transport in his contribution to the debate described my risk compensation hypothesis as “dubious and not proven”, but made no mention of his own department’s study whose conclusions supported mine. And my principal champion (Ivan Lawrence) described my findings as “astonishing and unexpected”. Such, at the time was the response to explanations of road accident statistics that invoked the risk compensation hypothesis.
http://www.john-adams.co.uk/2007/01/04/seat-belt-legislation-and-the-isles-report/Robert Davis, on page 80 of
Death on the Streets quotes the Isles Report.
claims for seat belt law effects were exaggerated, and that the likely effects in Britain would be either minimal or negative benefits for car users and an increase in deaths and injuries for people outside cars
The study (of the effects after the law had been passed) to which I have already referred, bore out the finding that a seat belt law would cost the lives of vulnerable road users.
This study was published in
Significance, the journal of The Royal Statistical Society and was written by three seat belt proponents who were also members of the Parliamentary Advisory Committee on Traffic Safety.
They say “the clear reduction in death and injury to car occupants is appreciably offset by extra deaths among pedestrians and cyclists.”
.
http://www.john-adams.co.uk/2013/03/24/the-biggest-lie/The idea that people's behaviour is unaffected by how safe they feel seems, to say the least, counterintuitive.
Two professors of statistics, Durbin and Harvey, were asked by the DoT to look at the question.
They concluded:-
The large estimated increases of pedestrian and cyclist fatalities suggest the possibilty of some change in driving behaviour by some drivers of cars and light goods vehicles after the introduction of the seat belt law.
It is, of course, impossible to examine the mental processes of all these drivers, but the evidence from their driving is clear.