Metodología del desarrollo de software

A precautionary approach to policy is often understood to be opposed to the standard

model of risk identification and risk-management, identified with the tools of RCBA.4 In

this section, I shall outline this approach. To understand the concept of ‘risk’ and the

methodology of RCBA, it is useful to consider the model of rational choice theory from which RCBA derives. Imagine that I want to buy a sandwich. I can either go to Shop A next door, which makes awful sandwiches, or to Shop B on the other side of town, which makes delicious sandwiches. These two courses-of-action have different benefits associated with

them– an awful sandwich or a delicious sandwich – and they have different costs associated

with them, a short walk or a long walk. The alternative courses-of-action might also be associated with different probabilities of suffering harm: going to Shop B involves crossing a busy road, thereby running a small probability of serious injury, whereas popping next

door does not. The term‘risk’, as used in its ‘Royal Society’ sense, is typically used to denote

such possibilities of suffering harm: we say that there is a risk associated with going to the

far-off shop, and no risk (or comparatively low) risk associated with popping next door.5

Sometimes we say that we would not be willing to run a risk of serious harm for any potential benefit. However, our behaviour often runs contrary to this platitude. I, for one, regularly run all sorts of risks of serious harm for the sake of minor benefits, although I would not run much higher risks of harm for the same benefits. I regularly run a small risk of being run over in return for a tasty sandwich, but would not run a much higher risk of harm for the same sandwich. So doing does not seem irrational. Indeed, not to do so would be to lead to a dreadfully impoverished life. One way in which to model these kinds of everyday decisions is to say that I act (or ought to act) in accordance with the goal of maximizing my overall expected utility. For example, we can model my decision thus:

Expected utility of going to Shop B¼ (value of tasty sandwich) plus (negative value of walking so far) plus (probability of being hit by a car multiplied by negative value of being hit by a car).

The greater the probability of serious injury attached to my walk to the shop, the lower my expected utility, and the more attractive the option of popping next door instead (where the expected utility of doing so is simply value of awful sandwich minus cost of walking a short

distance).6

RCBA applies a version of this model at the social level as a guide to policy. We choose between different policies by asking what the certain costs and benefits and risks associated with each of those policies are. Our choice, then, is guided by asking which action has the best expected outcomes. Of course, the use of RCBA in policy-making is not straightfor- ward. However, very roughly, the idea is simple: first, we construct a single scale along

4 _{For useful introductions to RCBA see Shrader-Frechette (1980) and Sunstein (2002). Note that,}

strictly, there are differences between the claims made by proponents of RCBA, by proponents of cost benefit analysis and by proponents of risk-trade-off-analysis. For our purposes, however, these differences are relatively unimportant.

5 _{Although we should note that the term ‘risk’ can be used in other ways, leading to some confusion.}

For a useful overview, see Hansson (2007).

6 _{This is a very simplified model of the kind of theory proposed by such writers as Luce and Raiffa}

(1958). For a useful history of the relevant arguments (which makes clear the link between developments in the theory of risk and the collection of epidemiological statistics) see Hacking (1975) and Hacking (1990).

which we can compare all possible benefits and costs of potential outcomes of action (normally, a monetary scale is used for these purposes). We can then compare different policies by comparing the expected costs and benefits of those actions (by multiplying the probability of those outcomes by their magnitude). It is important to recognize here that many people find the idea of constructing a single scale along which we might compare all outcomes of action to be morally suspect. I will return to these issues below. However, before going further, it is important to note that treating disparate outcomes as commen- surable seems to be consistent with everyday life: someone who regularly refused to trade- off risks of death against even such minor pleasures as a tasty sandwich would seem very strange.

I have identified two substantive aspects of RCBA. First, there is a claim about how we ought to reason: we ought to aim to maximize our expected utility. Second, a claim that we can place all costs, benefits and risks on a unitary scale, such that we can rank risks from most to least serious by multiplying the extent of harm associated with some event by the probability of that event. This way of thinking about policy-making is extremely powerful as a tool for thinking about public health policy, most notably health-and-safety policy. After all, we do think that there are limits on which public health policies we ought to

pursue; even if obtainable,‘safety at any cost’ would not necessarily be reasonable: RCBA

seems to provide us with a way in which to quantify such judgments.7

There are two necessary conditions for any philosophical defence of some government

policy tool: a condition of practicability and a condition of justifiability. By‘practicability’,

I mean that it should be clear how we ought to apply any proposed tool for policy-making. Although sometimes fraught in practice, as noted above, it is clear how RCBA should be applied in practical contexts. However, a defence of any policy tool should also meet a justifiability constraint. This task is particularly difficult in societies such as ours where there is widespread ethical disagreement. Therefore, I suggest that a defence of a policy tool should show how that tool relates to the political principles which constitute what Rawls

calls a‘free-standing module’, on which there can be an ‘overlapping consensus’. That is, we

should be able to defend use of a policy tool in such a way that different members of our community can agree to use of this tool for policy-making, regardless of their own views of the good life (Rawls, 1993). One key advantage of standard models of RCBA is that they are

supposed to be‘ethically neutral’, and, thus, to meet this publicity condition.

This may appear puzzling. After all, RCBA obviously involves placing some kind of

valuation on different outcomes, and the justification of such valuations– say, treating a

human life as‘costing’ £x million – may seem extremely difficult. However, typically, the

value-inputs into RCBA are supposed to be generated by adopting citizens’ own valuations of different outcomes. The value claims necessary for comparing risks are generated either by looking at individuals’ behaviour or by a process whereby their preferences between different outcomes are elicited. In effect, then, by assuming that everyone always reasons so as to maximize expected utility, in the way set out in the sandwich case, we generate an account of what people do value, and base policy on such valuations. RCBA is supposed to be ethically neutral in that (at least in its pure form) it does not rest on an objectivist account of good and bad, but generates claims about value on the basis of what people

7 _{For a useful analysis of these tools as they apply in the context of railway safety, see Wolff (2002;}

actually do value. This process leads Cass Sunstein (2005a) to suggest that such procedures are justifiable because they promote citizens’ well-being – use of such tools avoids forcing

individuals to‘pay more’ for some good such as risk-reduction than they would be willing

to pay– and respect citizens’ autonomy – by respecting their valuations of outcomes.