Tag: discounting

It is commonplace to use cost–benefit analysis (CBA) in assessing public policies, such as whether to build a new hospital, road or rail line. Various attempts in the past few months have been made to use CBA in assessing policies to reduce the spread of the coronavirus. These have involved weighing up the costs and benefits of national or local lockdowns or other containment measures. But, as with other areas where CBA is used, there are serious problems of measuring costs and benefits and assessing risks. This is particularly problematic where human life is involved and where a value has to be attached to a life saved or lost.

Take the case of whether the government should have imposed a lockdown: an important question if there were to be a second wave and the government was considering introducing a second lockdown. The first step in a CBA is to identify the benefits and costs of the policy.

Identifying the benefits and costs of the lockdown

The benefits of the lockdown include lives saved and a reduction in suffering, not only for those who otherwise would have caught the virus but also for their family and friends. It also includes lives saved from other diseases whose treatment would have been put (even more) on hold if the pandemic had been allowed to rage and more people were hospitalised with the virus. In material terms, there is the benefit of saving in healthcare and medicines and the saving of labour resources. Then there are the environmental gains from less traffic and polluting activities.

On the cost side, there is the decline in output from businesses being shut and people being furloughed or not being able to find work. There is also a cost from schools being closed and children’s education being compromised. Then there is the personal cost to people of being confined to home, a cost that could be great for those in cramped living conditions or in abusive relationships. Over the longer term, there is a cost from people becoming deskilled and firms not investing – so-called scarring effects. Here there are the direct effects and the multiplier effects on the rest of the economy.

Estimating uncertain outcomes

It is difficult enough identifying all the costs and benefits, but many occur in the future and here there is the problem of estimating the probability of their occurrence and their likely magnitude. Just how many lives will be saved from the policy and just how much will the economy be affected? Epidemiological and economic models can help, but there is a huge degree of uncertainty over predictions made about the spread of the disease and the economic effects, especially over the longer term.

One estimate of the number of lives saved was made by Miles et al. in the NIESR paper linked below. A figure of 440 000 was calculated by subtracting the 60 000 actual excess deaths over the period of the lockdown from a figure of 500 000 lives lost which, according to predictions, would have been the consequence of no lockdown. However, the authors acknowledge that this is likely to be a considerable overestimate because:

It does not account for changes in behaviour that would have occurred without the government lockdown; it does not count future higher deaths from side effects of the lockdown (extra cancer deaths for example); and it does not allow for the fact that some of those ‘saved’ deaths may just have been postponed because when restrictions are eased, and in the absence of a vaccine or of widespread immunity, deaths may pick up again.

Some help in estimating likely outcomes from locking down or not locking down the economy can be gained by comparing countries which have taken different approaches. The final article below compares the approaches in the UK and Sweden. Sweden had much lighter control measures than the UK and did not impose a lockdown. Using comparisons of the two approaches, the authors estimate that some 20 000 lives were saved by the lockdown – considerably less than the 440 000 estimate.

Estimating the value of a human life

To assess whether the saving of 20 000 lives was ‘worth it’, a value would have to be put on a life saved. Although putting a monetary value on a human life may be repugnant to many people, such calculations are made whenever a project is assessed which either saves or costs lives. As we say in the 10th edition of Economics (page 381):

Some people argue ‘You can’t put a price on a human life: life is priceless.’ But just what are they saying here? Are they saying that life has an infinite value? If so, the project must be carried out whatever the costs, and even if other benefits are zero! Clearly, when evaluating lives saved from the project, a value less than infinity must be given.
Other people might argue that human life cannot be treated like other costs and benefits and put into mathematical calculations. But what are these people saying? That the question of lives saved should be excluded from the cost–benefit study? If so, the implication is that life has a zero value! Again this is clearly not the case.

In practice there are two approaches used to measuring the value of a human life.

The first uses the value of a statistical life (VSL). This is based on the amount extra the average person would need to be paid to work in a job where there is a known probability of losing their life. So if people on average needed to be paid an extra £10 000 to work in a job with a 1% chance of losing their life, they would be valuing a life at £1 000 000 (£10 000/0.01). To avoid the obvious problem of young people’s lives being valued the same as old people’s ones, even though a 20 year-old on average will live much longer than a 70 year-old, a more common measure is the value of a statistical life year (VSLY).

A problem with VSL or VSLY measures is that they only take into account the quantity of years of life lost or saved, not the quality.

A second measure rectifies this problem. This is the ‘quality of life adjusted year (QALY)’. This involves giving a value to a year of full health and then reducing it according to how much people’s quality of life is reduced by illness, injury or poverty. The problem with this measure is the moral one that a sick or disabled person’s life is being valued less than the life of a healthy person. But it is usual to make such adjustments when considering medical intervention with limited resources.

One adjustment often made to QALYs or VSLYs is to discount years, so that one year gained would be given the full value and each subsequent year would be discounted by a certain percentage from the previous year – say, 3%. This would give a lower weighting to years in the distant future than years in the near future and hence would reduce the gap in predicted gains from a policy between young and old people.


Given the uncertainties surrounding the measurement of the number of lives saved and the difficulties of assigning a value to them, it is not surprising that the conclusions of a cost–benefit analysis of a lockdown will be contentious. And we have yet to see what the long-term effects on the economy will be. But, at least a cost–benefit analysis of the lockdown can help to inform discussion and help to drive future policy decisions about tackling a second wave, whether internationally, nationally or locally.



  1. What are the arguments for and against putting a monetary value on a life saved?
  2. Are QALYs the best way of measuring lives saved from a policy such as a lockdown?
  3. If the outcomes of a lockdown are highly uncertain, does this strengthen or weaken the case for a lockdown? Explain.
  4. What specific problems are there in estimating the number of lives saved by a lockdown?
  5. How might the age distribution of people dying from Covid-19 affect the calculation of the cost of these deaths (or the benefits or avoiding them)?
  6. How might you estimate the costs to people who suffer long-term health effects from having had Covid-19?
  7. What are the arguments for and against using discounting in estimating future QALYs?
  8. The Department of Transport currently uses a figure of £1 958 303 (in 2018 prices) for the value of a life saved from a road safety project. Find out how this is figure derived and comment on it. See Box 12.5 in Economics 10th edition and Accident and casualty costs, Tables RAS60001 and RA60003, (Department of Transport, 2019).

Many politicians throughout the world,
not just on the centre and left, are arguing for increased spending on infrastructure. This was one of the key proposals of Donald Trump during his election campaign. In his election manifesto he pledged to “Transform America’s crumbling infrastructure into a golden opportunity for accelerated economic growth and more rapid productivity gains”.

Increased spending on inffrastructure has both demand- and supply-side effects.

Unless matched by cuts elsewhere, such spending will increase aggregate demand and could have a high multiplier effect if most of the inputs are domestic. Also there could be accelerator effects as the projects may stimulate private investment.

On the supply side, well-targeted infrastructure spending can directly increase productivity and cut costs of logistics and communications.

The combination of the demand- and supply-side effects could increase both potential and actual output and reduce unemployment.

So, if infrastructure projects can have such beneficial effects, why are politicians often so reluctant to give them the go-ahead?

Part of the problem is one of timing. The costs occur in the short run. These include demolition, construction and disruption. The direct benefits occur in the longer term, once the project is complete. And for complex projects this may be many years hence. It is true that demand-side benefits start to occur once construction has begun, but these benefits are widely dispersed and not easy to identify directly with the project.

Then there is the problem of externalities. The external costs of projects may include environmental costs and costs to local residents. This can lead to protests, public hearings and the need for detailed cost–benefit analysis. This can delay or even prevent projects from occurring.

The external benefits are to non-users of the project, such as a new bridge or bypass reducing congestion for users of existing routes. These make the private construction of many projects unprofitable, except with public subsidies or with public–private partnerships. So there does need to be a macroeconomic policy that favours publicly-funded infrastructure projects.

One type of investment that is less disruptive and can have shorter-term benefits is maintenance investment. Maintenance expenditure can avoid much more costly rebuilding expenditure later on. But this is often the first type of expenditure to be cut when public-sector budgets as squeezed, whether at the local or national level.

The problem of lack of infrastructure investment is very much a political problem. The politicians who give the go-ahead to such projects, such as high-speed rail, come in for criticisms from those bearing the short-run costs but they are gone from office once the benefits start to occur. They get the criticism but not the praise.


Are big infrastructure projects castles in the air or bridges to nowhere? The Economist, Buttonwood’s notebook (16/1/17)
Trump’s plans to rebuild America are misguided and harmful. This is how we should do it. The Washington Post, Lawrence H. Summers (17/1/17)


  1. Identify the types of externality from (a) a new high-speed rail line, (b) new hospitals.
  2. How is discounting relevant to decisions about public-sector projects?
  3. Why are governments often unwilling to undertake (a) new infrastructure projects, (b) maintenance projects?
  4. Is a programme of infrastructure investment necessarily a Keynesian policy?
  5. What accelerator effects would you expect from infrastructure investment?
  6. Explain the difference between the ‘spill-out’ and ‘pull-in’ effects of different types of public investments in a specific location. Is it possible for a project to have both effects?
  7. What answer would you give to the teacher who asked the following question of US Treasury Secretary, Larry Summers? “The paint is chipping off the walls of this school, not off the walls at McDonald’s or the movie theatre. So why should the kids believe this society thinks their education is the most important thing?”
  8. What is the ‘bridge to nowhere’ problem? Why does it occur and what are the solutions to it?
  9. Why is the ‘castles in the air’ element of private projects during a boom an example of the fallacy of composition?

The UK government has finally given the go-ahead to build the new Hinkley C nuclear power station in Somerset. It will consist of two European pressurised reactors, a relatively new technology. No EPR plant has yet been completed, with the one in the most advanced stages of construction at Flamanville in France, having experienced many safety and construction problems. This is currently expected to be more than three times over budget and at least six years behind its original completion date of 2012.

The Hinkley C power station, first proposed in 2007, is currently estimated to cost £18 billion. This cost will be borne entirely by its builder, EDF, the French 85% state-owned company, and its Chinese partner, CGN. When up and running – currently estimated at 2025 – it is expected to produce around 7% of the UK’s electricity output.

On becoming Prime Minister in July 2016, Theresa May announced that the approval for the plant would be put on hold while further investigation of its costs, benefits, security concerns, technological issues and safeguards was conducted. This has now been completed and approval has been granted subject to new conditions. The main one is that the government “will be able to prevent the sale of EDF’s controlling stake prior to the completion of construction”. This will allow the government to prevent change of ownership during the construction phase. Thus, for example, EDF, would not be allowed to sell its share of Hinkley C to CGN, which currently has a one-third share in the project. EDF and CGN have accepted the new terms.

After Hinkley the government will have a ‘golden share’ in all future nuclear projects. “This will ensure that significant stakes cannot be sold without the Government’s knowledge or consent.”

In return for their full financing of the project, the government has guaranteed EDF and CGN a price of £92.50 per megawatt hour of electricity (in 2012 prices). This price will be borne by consumers. It will rise with inflation from now and over the first 35 years of the power station’s operation. It is expected that the Hinkley C will have a life of 60 years.

Critics point out that this guaranteed ‘strike price’ is more than double the current wholesale price of electricity and, with the price of renewables falling as technology improves, it will be an expensive way to meet the UK’s electricity needs and cut carbon emissions.

Those in favour argue that it is impossible to predict electricity prices into the distant future and that the certainty this plant will give is worth the high price by current standards.

To assess the desirability of the plant requires an assessment of its costs and benefits. In principle, this is a relatively simple process of identifying and measuring the costs and benefits, including external costs and benefits; discounting future costs and benefits to give them a present value; weighting them by their probability of occurrence; then calculating whether the net present value is positive or negative. A sensitivity analysis could also be conducted to show just how sensitive the net present value would be to changes in the value of specific costs or benefits.

In practice the process is far from simple – largely because of the huge uncertainty over specific costs and benefits. These include future wholesale electricity prices, unforeseen problems in construction and operation, and a range of political issues, such as pressure from various interest groups, and attitudes and actions of EDF and CGN and their respective governments, which will affect not only Hinkley C but other future power stations.

The articles look at the costs and benefits of this, the most expensive construction project ever in the UK, and possibly on Earth..


Hinkley Point: UK approves nuclear plant deal BBC News (15/9/16)
Hinkley Point: What is it and why is it important? BBC News, John Moylan (15/9/16)
‘The case hasn’t changed’ for Hinkley Point C BBC Today Programme, Malcolm Grimston (29/7/16)
U.K. Approves EDF’s £18 Billion Hinkley Point Nuclear Project Bloomberg, Francois De Beaupuy (14/9/16)
Hinkley Point C nuclear power station gets government green light The Guardian, Rowena Mason and Simon Goodley (15/9/16)
Hinkley Point C: now for a deep rethink on the nuclear adventure? The Guardian, Nils Pratley (15/9/16)
Hinkley Point C finally gets green light as Government approves nuclear deal with EDF and China The Telegraph, Emily Gosden (15/9/16)
UK gives go-ahead for ‘revised’ £18bn Hinkley Point plant Financial Times, Andrew Ward, Jim Pickard and Michael Stothard (15/9/16)
Hinkley Point: Is the UK getting a good deal? Financial Times, Andrew Ward (15/9/16)
Hinkley Point is risk for overstretched EDF, warn critics Financial Times, Michael Stothard (15/9/16)
Hinkley C must be the first of many new nuclear plants The Conversation, Simon Hogg (16/9/16)


Nuclear power in the UK National Audit Office, Sir Amyas Morse, Comptroller and Auditor General (12/7/16)


  1. Summarise the arguments for going ahead with Hinkley C.
  2. Summarise the objections to Hinkley C.
  3. What categories of uncertain costs and uncertain benefits are there for the project?
  4. Is the project in EDF’s interests?
  5. How will the government’s golden share system operate?
  6. How should the discount rate be chosen for discounting future costs and benefits from a project such as Hinkley C?
  7. What factors will determine the wholesale price of electricity over the coming years? In real terms, do you think it is likely to rise or fall? Explain.
  8. If nuclear power has high fixed costs and low marginal costs, how does this affect how much nuclear power stations should be used in a situation of daily and seasonal fluctuations in demand?
  9. How could ‘smart grid’ technology smooth out peaks and troughs in electricity supply and demand? How does this affect the relative arguments about nuclear power versus renewables?

Economic journalists, commentators and politicians have been examining the possible economic effects of a Yes vote in the Scottish independence referendum on 18 September. For an economist, there are two main categories of difficulty in examining the consequences. The first is the positive question of what precisely will be the consequences. The second is the normative question of whether the likely effects will be desirable or undesirable and how much so.

The first question is largely one of ‘known unknowns’. This rather strange term was used in 2002 by Donald Rumsfeld, US Secretary of Defense, in the context of intelligence about Iraq. The problem is a general one about forecasting the future. We may know the types of thing that are likely happen, but the magnitude of the outcome cannot be precisely known because there are so many unknowable things that can influence it.

Here are some known issues of Scottish independence, but with unknown consequences (at least in precisely quantifiable terms). The list is certainly not exhaustive and you could probably add more questions yourself to the list.

Will independence result in lower or higher economic growth in the short and long term?
Will there be a currency union, with Scotland and the rest of the UK sharing the pound and a central bank? Or will Scotland merely use the pound outside a currency union? Would it prefer to have its own currency or join the euro over the longer term?
What will happen to the sterling exchange rate with the dollar, the euro and various other countries?
How will businesses react? Will independence encourage greater inward investment in Scotland or will there be a net capital outflow? And either way, what will be the magnitude of the effect?
How will assets, such as oil, be shared between Scotland and the rest of the UK? And how will national debt be apportioned?
How big will the transition costs be of moving to an independent Scotland?
How will independence impact on Scottish trade (a) with countries outside the UK and (b) with the rest of the UK?
What will happen about Scotland’s membership of the EU? Will other EU countries, such as Spain (because of its concerns about independence movements in Catalonia and the Basque country), attempt to block Scotland remaining in or rejoining the EU?
What will happen to tax rates in Scotland, with the new Scottish government free to set its own tax rates?
What will be the consequences for Scottish pensions and the Scottish pensions industry?
What will happen to the distribution of income in Scotland? How might Scottish governments behave in terms of income redistribution and what will be its consequences on output and growth?

Of course, just because the effects cannot be known with certainty, attempts are constantly being made to quantify the outcomes in the light of the best information available at the time. These are refined as circumstances change and newer data become available.

But forecasts also depend on the assumptions made about the post-referendum decisions of politicians in Scotland, the rest of the UK and in major trading partner countries. It also depends on assumptions about the reactions of businesses. Not surprisingly, both sides of the debate make assumptions favourable to their own case.

Then there is the second category of question. Even if you could quantify the effects, just how desirable would they be? The issue here is one of the weightings given to the various costs and benefits. How would you weight distributional consequences, given that some people will gain or lose more than others? What social discount rate would you apply to future costs and benefits?

Then there are the normative and largely unquantifiable costs and benefits. How would you assess the desirability of political consequences, such as greater independence in decision-making or the break-up of a union dating back over 300 years? But these questions about nationhood are crucial issues for many of the voters.


Scottish Independence would have Broad Impact on UK Economy NBC News, Catherine Boyle (9/9/14)
Scottish independence: the economic implications The Guardian, Angela Monaghan (7/9/14)
Scottish vote: Experts warn of potential economic impact BBC News, Matthew Wall (9/9/14)
The economics of Scottish independence: A messy divorce The Economist (21/2/14)
Dispute over economic impact of Scottish independence Financial Times, Mure Dickie, Jonathan Guthrie and John Aglionby (28/5/14)
10 economic benefits for a wealthier independent Scotland Michael Gray (6/3/14)
Scottish independence, UK dependency New Economics Foundation (NEF), James Meadway (4/9/14)
Scottish Jobs and the World Economy Scottish Economy Watch, Brian Ashcroft (25/8/14)
Scottish yes vote: what happens to the pound in your pocket? Channel 4 News (9/9/14)
What price Scottish independence? BBC News, Robert Peston (12/9/14)
What price Scottish independence? BBC News, Robert Peston (7/9/14)
Economists can’t tell Scots how to vote BBC News, Robert Peston (16/9/14)

Books and Reports
The Economic Consequences of Scottish Independence Scottish Economic Society and Helmut Schmidt Universität, David Bell, David Eiser and Klaus B Beckmann (eds) (August 2014)
The potential implications of independence for businesses in Scotland Oxford Economics, Weir (April 2014)


  1. What is a currency union? What implications would there be for Scotland being in a currency union with the rest of the UK?
  2. If you could measure the effects of independence over the next ten years, would you treat £1m of benefits or costs occurring in ten years’ time the same as £1m of benefits and costs occurring next year? Explain.
  3. Is it inevitable that events occurring in the future will at best be known unknowns?
  4. If you make a statement that something will occur in the future and you turn out to be wrong, was your statement a positive one or a normative one?
  5. What would be the likely effects of Scottish independence on the current account of the balance of payments (a) for Scotland; (b) for the rest if the UK?
  6. How does inequality in Scotland compare with that in the rest of the UK and in other countries? Why might Scottish independence lead to a reduction in inequality? (See the chapter on inequality in the book above edited by David Bell, David Eiser and Klaus B Beckmann.)
  7. One of the problems in assessing the arguments for a Yes vote is uncertainty over what would happen if there was a majority voting No. What might happen in terms of further devolution in the case of a No vote?
  8. Why is there uncertainty over the amount of national debt that would exist in Scotland if it became independent?

The enormous amounts of money broadcasters are willing to pay for the rights to show live football astonish most people. The figures have continued to rise despite the impact of a recession, slow economic growth and static or falling real incomes.

The deal to broadcast live games in the English Premier League (EPL) for the three seasons from 2007-10 was 65% higher than the agreement that ran from 2004-07. The recession did appear to slow growth down as the contract covering the seasons 2010-13 was only 5% higher than the previous one. However the total size of this deal was still a staggering £1.78billion or approximately £593 million per season. BSkyB was the most successful bidder in all of these auctions for live TV rights and successfully saw off competition from ITV Digital, ESPN and Setanta.

However in the last few years, BT Sport has entered the bidding process and has provided BSkyB with much stronger competition than its previous rivals. As a result, BskyB had to pay £2.3 billion in order to outbid BT Sport in the most recent auction. The three-year deal beginning in the 2013-14 season gives BSkyB the rights to show 116 lives matches each year. BT Sport also paid £738 million for the rights to show 38 live matches a season. In total this means that the EPL earns approximately £1billion per season from the sale of broadcasting rights in the domestic market – an increase of 70%!

The Champions and Europa League also auction the rights to broadcast live matches and there was a real shock when BT Sport recently announced that it had secured the exclusive rights to show all 350 live games in these competitions. Once again the figure it paid – just under £900 million for a three-year deal – took most people by surprise. It represented a 125% increase on the previous three-year deal with BSkyB and ITV. What was also surprising was that there was only one round in the sealed bid auction which suggests that BT Sport’s offer was well in excess of the one submitted by BSkyB.

Most of the initial reaction to this new deal has focused on its implications for the number of matches that will be available free to air: i.e. without having to pay for a subscription channel. The BT Sport contract does specify that the Champions League final and at least one match involving each British team will be shown free to air each season. However, this will be a significant reduction in the number of free to air games currently shown by ITV.

The new deal may also have implications for competitive balance in the EPL. This concept was discussed in a previous blog on this New Site Parachute payment problems for the English Football League and refers to how equally the most talented players are distributed amongst the teams in a league. This distribution will be heavily influenced by the degree to which the revenues of the teams in the league vary. Commenting on this latest contract Liverpool’s former managing director Christian Purslow stated that:

The fundamental effect of the BT deal will be additional wealth for England’s big teams. You will now have six teams (Manchester City, Chelsea and Manchester United, Arsenal, Liverpool and Spurs) playing for four Champions league places with the other 14 teams playing for survival. Never again will the likes of Everton, Newcastle or Villa get near the top – the difference in revenues will simply be too great.

To understand this statement one has to examine how the Champions League distributes the revenue it raises back to the teams that participate in the tournament. One part of the distribution mechanism is determined by the sporting performance of the teams in the competition. For example all 32 teams that make it to the group stages of the Champions League receive a minimum of €8.6 million. Each win in the group games earns a team an additional €1 million while a draw earns €500,000. The teams that make it to the last 16 receive an additional payment of €3.5 million, the quarter finalists earn an additional €3.9 million while the semi-finalists each receive €4.9 million. For example in the 2012-13 season, Manchester United received prize money of €16.1 million for reaching the last 16, whereas Bayern Munich received €35.9 million of prize money for winning the competition. If broadcasting revenues for the Champions League increase across the whole of Europe then the size of the prizes will almost certainly increase.

Teams also receive a share of the broadcasting revenue generated by the Champions League known as the market pool. The total size of the market pool allocated to the teams in any particular country depends on the value of the deal between the broadcasters in that country and UEFA. In the 2012-13 season the total market pool to be divided between the four English teams in the Champions League was €86.6 million. This was the second highest figure behind Italy. In contrast the four Portuguese teams had just over €7 million from the market pool to share between them because the value of the broadcasting deal in that country was so much lower. The market pool is split between the clubs based on (a) their finishing position in the domestic league the previous season and (b) how many games they played in the Champions League from the group stage onwards. FC BATE Borisov were the only representative from Belarus so did not have to share the market pool with any other team. Unfortunately for them the size of the market pool was only €290,000. Manchester United received a market pool payment of €19.45 million.

Given the dramatic increase in value of the broadcasting rights the size of the market pool for the English teams will rise significantly in 2015-16 season. The battle in the 2014-15 EPL season for the four Champions League places will be even stronger and more intense than ever. As a result, the competition for the services of the most talented players will probably push up their wages to ever higher levels.

Monopoly money: Football’s TV war makes the rich unreachable’ BBC Sport (17/11/13)
Champions League TV deal in focus BBC Business (11/11/13)
Champions League: BT Sport wins £897 football rights deal BBC Sport (9/11/13)
Top Soccer Leagues Get 25% Rise in TV Rights Sales, Report Says Bloomberg (11/11/13)
BSkyB could face Premier League premium The Guardian (11/11/13)
Clubs benefit from Champions League revenue UEFA (23/7/13)
Sky pleaded with football officials to reopen champions league talks The Telegraph (11/11/13).


  1. What is a sealed bid auction? How does it compare with different types of auctions?
  2. Suggest some reasons why BT Sport were willing to pay so much more than BSkyB for the broadcasting rights for the Champions League.
  3. Do you think that the potentially higher revenues for the top clubs might actually reduce attendances at their matches? Explain your answer.
  4. Explain how the potentially higher future revenues for teams participating in the Champions League in 2015-16 can be discounted in order to give them a present value.
  5. Draw a diagram to illustrate the impact of the new broadcasting deal on the marginal revenue product of the most talented players.
  6. Is the labour market for the most talented players competitive or is it an oligopsony? What implications does this have their wages? How does your answer change if the labour market is a bilateral monopoly?