1 Cost-Benefit Analysis in Welfare Economics
The basic theory of welfare economics enables one
to identify how far the market is operating ‘efficiently’. This is
taken to mean how far the market allocates resources in such a way
as to make the maximum contribution – given resources and technical
knowledge – to society’s economic welfare. Welfare economics
provides the criteria necessary for this purpose. This includes the
well-known rules that any student of economics would know, such as
the relationship between prices and social costs. Satisfaction of
these rules is supposed to ensure that society is operating at a
point where no reallocation of resources can raise one person’s
utility without reducing somebody else’s utility. Such a point is
known as a ‘Pareto optimum’ point, in honour of the great
nineteenth-century Italian sociologist and economist, Vilfredo
Pareto.
Before proceeding to examine the criteria of an
efficient allocation of resources, however, it should be noted
that, as the Nobel Laureate Joseph Stiglitz has put it,
‘Unemployment – the inability of the market to generate jobs for so
many citizens – is the worst failure of the market, the greatest
source of inefficiency.…’1 Since recurrent periods of very high
unemployment have characterised developed economies for over a
century, it might appear that analysing the ‘efficiency’ with which
resources are allocated, when so many are just not allocated
anywhere at all, is a flagrant example of the old warning against
swallowing a camel while straining at a gnat. Nevertheless, given
the level of resource used at any time – which is a matter of
macro-economic policy – there are still innumerable problems of
resource allocation to be faced. There is no point in making what
may be a bad situation worse by misallocating such resources as are
employed. So this book is about the allocation of resources in the
market at any point of time.
In practice, of course, there is not just one
market. The economy is made up of innumerable markets. There are
labour markets, financial markets, second-hand markets, online
markets, covered markets, commodity markets, housing markets, and
so on. But do these markets all operate in a way that will maximise
their potential contribution to society’s economic welfare? Most
people would say, quite reasonably, that one does not need any
fancy theory to conclude that financial markets have been behaving
disastrously over the ages. But here we are concerned with other,
less ‘special’ markets. And it is the theory of welfare economics
that shows why most markets will generally fail to make the maximum
contribution to economic welfare. It is welfare economics that
demonstrates that there are likely to be instances of what are
known in the jargon as ‘market failure’ – that is, a failure of
markets to make their full potential contribution to society’s
economic welfare.
There are various well-known forms of market
failure. The most widely known include what are known as ‘negative
externalities’: aircraft and trucks can produce a lot of noise,
some factories emit poisonous emissions from their chimneys, and so
on. Other goods or services may not be produced up to the socially
desirable level on account of some monopolistic restriction, or a
serious imbalance between the information available to buyers and
sellers, or taxes or tariffs. Welfare economics identifies these
‘market failures’ and the criteria by which the socially
‘efficient’ level of such activities can be determined.
Thus the basic theory of welfare economics has
much to contribute to the promotion of society’s economic welfare.
When any particular instance of ‘market failure’ is identified
there is often a prima
facie case for some policies to rectify the matter.
Sometimes this may indicate a prima facie case for government
intervention. But ‘government failure’ is sometimes likely to be as
bad as market failure, if not worse, as when policies are
introduced as a result of the influence of particular pressure
groups or administrators. Some changes of policy concerning the
subsidisation of offshore wind farms, or ‘fracking’, or investment
in ‘prestige projects’ are modern examples.
And, as everybody will have noticed, governments
play a big part in the operation of most markets. All markets are
affected by government taxes and subsidies. In the labour market
many countries have legal minimum wages or restrictions on the age
at which people may be employed. In financial markets, banks are
usually subject to certain regulations, though these do not seem to
have been very effective lately. Government subsidies to financial
institutions by bailing them out when they would otherwise have
collapsed may well have helped sustain the instability of financial
institutions. In many countries governments are also the main
agents in the market for certain goods or services, such as medical
services, education, national defence, infrastructure such as
transport, and what passes for law and order in our cities. Under
what conditions are all such forms of government intervention
justified? By what criteria can one judge when the market is not
performing well?
Welfare economics helps identify these criteria.
And it may also help to identify possible cures. For example, it
enables one to identify what tax ought to be imposed on some
polluting activity if that is to be the preferred way of ensuring
that polluters take account of the full social costs of the
activity in question.
2 Cost-Benefit Analysis and ‘Franklin’s Algebra’
In practice, what is generally known as
‘cost-benefit analysis’ (CBA) is an essential tool of welfare
economics. For it enables one to establish whether the economic
benefits of a project exceed the costs and hence whether the
conditions of a Pareto-optimising move can be satisfied (leaving
aside distributional considerations). In its most general form
‘cost-benefit analysis’ resembles what Cass Sunstein has called
‘Franklin’s Algebra’, namely a list of all the pros and cons of any
particular decision.2
This decision tool, which was set out in a letter by Benjamin
Franklin in 1772, is not necessarily confined to economic
considerations or quantifiable inputs. But such economic
considerations – including even those that are quantifiable – that
enter into a comparison of the pros and cons of any choice are
invariably influenced by ethical considerations in two main
ways.
First, they influence what factors are included
in the economic part of any more general comparisons of the pros
and cons of any particular policy. Should the analysis be confined
to the ‘efficiency’ with which resources are allocated in the
economy or should account also be taken of the effect of any policy
on the distribution of income or the welfare of particular groups
within one’s country or abroad? For example, consider the provision
of health care to poor people, or an appraisal of some trading
arrangement such as the export of toxic waste or the protection of
domestic agriculture, or industry. How far can beneficence towards
poorer groups or countries be taken into account in the
analysis?
Second, even when the scope of the CBA has been
settled, ethical considerations also affect the prices attached to
the relevant costs and benefits. The gap between people’s revealed
preferences and their welfares that has been discussed in
Chapter
5 clearly affects the welfare significance of the
pattern of prices on the market. For if people often make choices
that do not really reflect their welfares, the market prices may
not always correspond to the welfare of the market participants in
question. Should one adjust downwards the prices for some items
that enter into a CBA if we believe that the goods and services in
question are really bad for the people who buy them, or,
conversely, are better for the consumers than they know so that
they really ought to buy more of them? That is, if the prevailing
market price does not adequately reflect the contribution made by
the goods or services in question to their welfare.
Third, prices used in a CBA of some facilities
can be distorted as a result of the ‘commodification’ of certain
goods and services to which reference was made in Chapter 5. Elizabeth Anderson points
out that these prices are often based on surveys of how much people
would be prepared to pay for the facilities in question, such as
the provision of parks, or improvements in the local environment,
or recreational facilities, or improvements in safety.3 But these prices will
usually reflect – mainly or solely – people’s desires for the goods
and services for their own use, rather than their valuations of
them as facilities that are shared by members of society, including
perhaps goods that they do not even expect to use themselves. So a
CBA based on these prices assumes that the goods in question fulfil
only the same indiscriminate want-satisfaction function that is
provided by market transactions in ordinary commodities. This also
means that the preferences of richer people will have more weight
than those of poor people, which may be undesirable for certain
categories of goods and services that are publicly provided.
3 Pareto Optimality and the Compensation Test
As stated earlier, the whole point of an economic
CBA is that it shows whether – abstracting from all non-economic
considerations and distributional values – the adoption of the
project in question would enable somebody to be made economically
better off without anybody else being worse off. For if the
economic benefits exceed the costs it is theoretically possible for some of the
benefits to be transferred from the potential beneficiaries of the
project to the potential losers and still leave something over for
the former. In other words, the beneficiaries could still have
gained even if they have fully compensated the losers. Such a move,
therefore, would enable the economy to move towards what has been
defined previously as a Pareto optimum point. It is called a
‘Pareto optimising
move’.
If compensation is actually carried out – that
is, the move satisfies what is known as the ‘Hicks/Kaldor
compensation test’ in honour of its originators, John Hicks and
Nicholas Kaldor – the move can be judged to have increased the
combined utility of all parties concerned without having to make
interpersonal comparisons of utility. This is because there is no
need to compare how much utility the gainers gain with how much
utility the losers lose. For, after compensation, the losers will
have lost nothing.
But an excess of benefits over costs only shows
that it is theoretically
possible for the gainers to compensate the losers while remaining
better off. Whether the compensation is actually carried out or not is another
matter. For this reason a distinction is made between a
‘potential’ Pareto
optimising move and an ‘actual’ Pareto optimising move. And the
distinction may often be very important, as illustrated in Section
5.
4 Practical Limitations on the Compensation Test
To begin with there are various practical
difficulties involved in making the transfer from the beneficiaries
to the losers. First, the mere act of making the transfers from the
gainers to the losers may involve costs – that is, some new kind of
losses. If the transfers take the form of taxes and benefits these
could, in theory, distort resource allocation as well as incur
administrative costs. For example, they may distort people’s
incentives to work or invest. So total output (and hence
prosperity) may be reduced more than is gained by the improved
resource allocation.
Second, it may often be impossible to identify
who are the gainers and who are the losers from any project.
Consider, for example, a CBA of the location of a new airport. In
transport studies the name of the game is usually time – that is,
time saved. Suppose that the new airport saves time for the airline
passengers to reach their final destination. For business
travellers this will be a gain to their companies, or their
companies’ shareholders, who may include some insurance companies
who have obligations to pay out pensions to retired people. How is
one to track down all the individual pensioners and others who may
gain indirectly through the project? Obviously impossible. So who
would pick up the bill in the end to compensate the losers, such as
the people who may have to put up with environmental damage? The
taxpayer, perhaps? But this just creates a new class of
uncompensated losers.
Third, the costs and benefits have to be ‘cleaned
up’ to allow for market distortions, such as those mentioned
earlier, namely the existence of taxes and benefits, or
externalities, or imperfect competition. This adjustment from
observable market prices to what are known as ‘shadow prices’ that
are supposed to bear a closer relationship to real social costs and
benefits will usually be a highly speculative operation, though in
certain circumstances a fairly good approximation can be achieved.
However, it does mean that some projects should only be assumed to
be desirable if there is a substantial excess of benefits over
costs. But, on account of certain theoretical considerations to
which we shall now turn, even this is not always a compelling
criterion.
5 Pareto Optimality and the Distribution of Incomes
But the biggest limitation on the role of an
economic CBA is its neglect of distributional considerations. It is
true that, at first sight, a ‘Pareto-optimising’ move that can make
somebody better off without anybody being worse off would seem to
be ethically compelling. All that it requires is a little bit of
the spirit of beneficence. The trouble is that there are an
indeterminate number of Pareto optimal points, corresponding to
very different distributions of utility. Consider two people, Smith
and Jones, who have been washed up on a desert island. They find
that they can manage to catch ten fishes every day (or ten fishes
jump out of the sea every day). And let us assume that both like
fish. But Smith is a big, tough and selfish person, without a shred
of egalitarian or altruistic instincts in him. So every day he
eats, with relish, nine of the fish and leaves only one for Jones.
But the position is Pareto optimal, since any increase in Jones’s
share of the fish must mean a reduction in Smith’s share of the
fish. The same would apply if Smith appropriated eight fish every
day, or any number of the fish.
In fact, in this example, there are eleven
possible ways in which the fish are shared out, ranging from Smith
eating all of them to his eating none of them. All of them would be
Pareto optimal points. And in a complex economy with hundreds and
thousands of different resources and products there will be a vast
indeterminate number of Pareto optimal points, each of which will
represent a different distribution of utilities. It is for this
reason that Amartya Sen has written that ‘a situation may be Pareto
optimal but be perfectly disgusting’.4 So Pareto optimality may not be such
a big deal. It is compatible with any degree of inequality in the
distribution of utility, which may, in practice, be closely related
to the inequality in the distribution of incomes.

Fig.
7.1
A ‘Utility Possibility Frontier’
Figure 7.1 shows the relationship of the utility of Mrs
A up the vertical axis to the maximum utility that can be enjoyed
by Mrs B along the horizontal axis, given the economy’s resources.
It corresponds to the ‘budget line’ that plays a crucial part in
the elementary theory of how a consumer distributes her
expenditures between two goods, given their relative prices and the
constraint on her total expenditures. In a similar manner, this
Utility Possibility Frontier (UPF) indicates how society could
distribute utility between individuals or groups A and B, given its
resources and technical knowledge.
In the previous diagram, starting from any point
on the Utility Possibility Frontier, no move could be justified in
terms of the Pareto criterion however much it might mean moving to
what society would deem to be a more equitable income distribution.
For, by definition of a UPF, somebody must lose by the move. So a
point on the UPF at which one agent is very poor and another is
very rich is just as Pareto optimal as one where the utilities are
shared out more equally. How could society identify which
particular point on its UPF corresponds to its optimal choice of
how utilities ought to be distributed in society? A method of doing
so is analogous to the method used in elementary economic theory to
show how an individual consumer chooses her optimal combination of
the goods available to her given their prices and her income.
In this theory the consumer selects the optimum
distribution of her consumption between various goods (given their
prices and her income) in the light of her relative preferences
between the goods in question. Diagrammatically, this is shown in a
two-good figure as the point at which the budget line representing
her constraint is tangential to the highest indifference curve she
can reach, given her relative preferences between different
combinations of the goods in question. At the level of society’s
choice between different feasible distributions of utility, what is
needed then is to add some function that represents society’s
preferences between different distributions of the utilities
accruing to the various members of society. This is provided by the
concept of a ‘social welfare function’, which will be explained in
the next section.
6 Introducing the ‘Social Welfare Function’
The introduction of the concept of a social
welfare function seems to provide an escape from the distributional
neutrality of the Pareto optimum. It provides a useful analytical
tool for clarifying the differences between various value
judgements concerning equality, though it is not necessarily
confined to this purpose. It can also be invoked in making
decisions about any project.
The standard concept of a social welfare function
in which the focal variable is consumption has been expressed in
the recent Stern Report on The
Economics of Climate Change as follows:
The objective of policy is taken to be the maximisation of the sum across individuals of social utilities of consumption.…In particular, we consider consumption as involving a broad range of goods and services that includes education, health and the environment. The relationship between the measure of social wellbeing – the sum of social utilities in this argument – and the goods and services consumed by each household, on which it depends, is called the social welfare function…(Stern, 2006, p. 30, Box 2.1; my italics)
In order to bring the social welfare function
into relation with the two-dimensional utility possibility frontier
in a two-person (or group) figure it needs to be in terms of
utilities. Thus one way of interpreting a social welfare function
is that it indicates the social value that one places on the
utility, or welfare, accruing to any individual. These values are
sometimes referred to as the ‘social utilities’ of the individuals’
consumption. Hence, economists have generally defined social
welfare as some function of individuals’ utilities, and abbreviated
versions of social welfare functions are generally written as
where W represents
society’s total (economic) welfare and U i represents the social value of
the expected utility of the ith individual. As indicated earlier,
this is not restricted to the utility an individual derives from
his income or his consumption of personal goods, but can include
other features of the state of affairs such as the degree of
equality. Arrow suggested that an individual’s preferences between
his own consumption bundles reflect his tastes, whereas his preferences between
other features of a social state, such as the degree of inequality
therein reflect his values,
though he pointed out that this distinction is by no means clear
cut [loc.cit.
p.18].5

(1)
The ‘social values’ attached
to individuals’ utilities in a social welfare function represent
mainly distributional values, though one may not attach a very high
social value to some of the ways in which some people derive
utility. But for present purposes, we shall focus on the
distributional values reflected in a social welfare function. For
example, one might attach less social value to a marginal increase in
the consumption of somebody who started off at a high level of
utility than to an equal marginal increase in the consumption of
somebody with a relatively low level of utility. In other words, we
shall assume that a social welfare function indicates primarily to
what extent – other things being equal – one prefers social states
that are more equal than others in terms of utilities.
There is, of course, no such thing as ‘the’
social welfare function. Different people will have different views
as to what are the most important variables that characterise any
particular social state as well as the degree of inequality in
society that should be promoted. For practical policy purposes, the
social welfare function that matters will be the social welfare
function of the decision makers. If they did not care about the way
utilities are distributed and simply wanted to maximise society’s
total utility they would prefer the following utilitarian social
welfare function, in which W is simply the arithmetic sum of
individual utilities and the distribution of utilities does not
come into it.
But most people do care about the way utilities are distributed
among the population. Most people would tend to attach more weight
to a unit of utility of a poorer person than to a richer person.
This would be the case if one subscribed to some form of
egalitarianism (see Chapter
16). In that case they may decide that social
welfare has increased even if an increase in the utility of the
poor person is accompanied by an equal, or greater, decrease in the
utility of the rich person. An egalitarian social welfare function
would thus be convex to the origin, rather like an ordinary
consumer’s indifference curve relating his preferences between,
say, apples and pears. Social welfare would depend on the
relative utilities of
people, as well as their absolute utilities. Figure 7.2 compares a utilitarian
and a mildly egalitarian social welfare function.

(2)

Fig.
7.2
How to reconcile efficiency with social
welfare
In Fig. 7.2, the point at which society reaches its
highest social welfare subject to the constraint given by the UPF
will, of course, be that point at which the UPF is tangential to
the highest attainable SWF. Only at such a point will it appear
that we have satisfied the necessary and sufficient conditions for
maximising social welfare, namely that we are on a UPF – that is, a
Pareto optimal position – but also reaching the highest possible
SWF. AS indicated earlier, this procedure is analogous to the
representation of the optimality of consumers’ choice in terms of
the tangency between his budget line (the counterpart of the UPF)
and his highest possible indifference curves (the counterpart of
the SWF). It can be seen from Fig. 7.2 that a mildly
egalitarian would prefer a point on the UPF at which the utilities
were fairly equally distributed between the two people, A and B. A
utilitarian, however, would maximise social welfare at point Y,
where there is a very unequal distribution of utility among the
agents in question.
For practical policy purposes, however, it is
more important to know that a very strong egalitarian might even
prefer some points inside a UPF to many points on the UPF. Hence, even a
Pareto-optimising move (i.e. one that involves no losers) does not
necessarily lead to an increase in social welfare. This would be
the case, for example, with a move from point I to point II in Fig.
7.3. For in
even though B finishes up with slightly more utility than before, A
has received far more additional utility. This means that
inequality has increased. And given society’s strong aversion to
inequality – as illustrated by the shape of its SWF – it has
actually moved to a lower SWF.

Fig.
7.3
Economic efficiency versus strong
egalitarianism
This seems to be precisely what has happened in
the Western world over the last two decades or so. As explained in
Chapter
15, although even the incomes of the worst off
have risen slightly, there has been a much greater increase in the
incomes of the richest group in society. The resulting increases in
inequality could well have contributed to greater friction and
resentment in society.
And conversely, a move from II to I leads to a
higher SWF even though it may well fail to satisfy the Pareto
optimisation criterion. Thus, for example, a project that led to a
slight improvement in the welfare of, say, poor workers (along the
horizontal axis) but at considerable loss to rich consumers of
their products (along the vertical axis) might be deemed desirable.
This might be the case if, say, if poor workers gained a little
welfare through more safety in their working environment, but rich
consumers in wealthy countries are estimated to lose more through
having to pay higher prices for the goods produced as a result of
the better safety regulation. In this case the distribution of
income has become more equal even after compensating the losers.
So, depending on the importance attached to distributional
considerations the Pareto optimality criteria is not a sufficient
condition for carrying out the project.
7 Conclusions
Overall, therefore, the introduction of the
social welfare function enables one to see clearly why, if
distributional considerations are taken into account, Pareto
optimality is neither a necessary nor a sufficient condition for an
improvement in social welfare. In simple terms this means that some
egalitarians might be willing to trade off a fall in national
income in the interests of greater equality. After all, this is a
judgement that most of us are prepared to make in many
circumstances and reflects the relative intrinsic value we attach
to equality and prosperity.
Of course one should not exaggerate the
distributional effects of any project. Quite often these will be
negligible as far as the whole society is concerned. But it may
often be important in a local context. For example some roads may
simply serve to help rich landowners or commuters get back home at
night, whereas other roads may help poor farmers get their produce
to market. There may well be cases where such distributional
considerations will outweigh a narrow comparison between social
costs and benefits that took no account of them. What the CBA does
is to show roughly how much it will cost in certain circumstances
to pursue greater equality. It is then up to society (or the
decision makers) to decide whether or not it is acceptable.
Furthermore, in a society in which numerous
projects are carried out, it may well be that what some people lose
on the swings they can more than gain on the roundabout. This is
more likely to be the case if the projects are calculated carefully
and correspond correctly to the economic concepts of social costs
and benefits.
Finally, it is always open to governments to
influence the final distribution of incomes in a more or less equal
manner, as it wishes, through the mechanism of fiscal policy.
Adjusting project evaluation as a means of achieving one’s
distributional objectives is not the only means available for
pursuing this objective. On the other hand, it cannot always be
assumed that any prevailing regime of taxes and benefits is optimal
given society’s egalitarian values.
However, although the concept of a social welfare
function `is a valuable tool in many areas of public policy, it is
also, in turn, subject to its own limitations. These are discussed
in the next chapter.
Bibliography
Anderson, E., 1999, ‘What Is
the Point of Equality?’, Ethics, 109.
Sen, A., 1970, Collective Choice and Social Welfare,
Holden-Day, San Francisco, and Oliver & Boyd, London.
Stern, N., 2006,
The Economics of Climate Change:
The Stern Review, Cambridge University Press.
Stiglitz, J., 2012,
The Price of Inequality,
Penguin Books, Harmondsworth, UK.
Sunstein, C., 2014,
Valuing Lives: Humanizing the
Regulatory State, University of Chicago.