Reasoning is based on evaluation because the legislature needs to work out the
value of each option. To evaluate the options, the legislature needs first to
determine the values which it will deploy in performing the task. In principle,
the legislature is entirely free to determine values as it will. In practice, though,
it will feel constrained, at least in a broad way, by the wishes of the electorate.
Once these values are determined, they enable a legislature to classify an effect
as a cost or a benefit and to measure its value in this regard.
Calculating net benefit when using values involves the following steps:
(1)
Add up each benefit to yield total benefits.
(2)
Add up each cost to yield total costs.
(3)
Subtract total costs from total benefits to give net benefit.
This process of ascertaining the net benefit of each effect of each possible
version of a statute, and using this to identify the best statute on a topic can be
represented in a diagram. In this diagram, the net benefits of Effects 0-n are
labelled Net Benefits 0-n:
Statutes
Effects
Net Benefit
Statute 0
Effect 0
Net Benefit 0
Statute 1
Effect 1
Net Benefit 1
Statute 2
Effect 2
Net Benefit 2
Statute n
Effect n
Net Benefit n
Figure 12.2 Statutes, Effects and Net Benefits
This discussion has presented net benefit in a simple way to enable readers to
grasp the basic concept. A fuller analysis of net benefit involves at least two
other considerations, which are discussed elsewhere. First, in practice it is
difficult if not impossible in many circumstances to calculate net benefit with
even reasonable accuracy because of the problem of incommensurability.
Some items are difficult or impossible to value and measure. Even if some
individual items can be measured, they may be measured on different scales so
that it is not possible to add and subtract their values as calculation of net
benefit requires.
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Second, in the example we calculated net benefit using the
nominal or face values of benefits and costs. If one wishes to incorporate the
uncertainty into the calculation, one means of doing this involves using
expected values in preference to nominal values.
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Step 3: Decision
Having calculated the net benefit of each effect by reference to either nominal
or expected values, the legislature then determines which effect produces the
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Christopher Enright Legal Reasoning Chapters 10-12
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Christopher Enright Legal Reasoning
Chapter
15 Cause: Responding to
Uncertainty
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