Autor: Rui Cunha Marques

Año: 2007

Fuente: Water Policy Journal


Rui Cunha Marques(1)
Assistant Professor at the Technical University of Lisbon. Civil Engineer,
M.Sc. (performance indicators), Post-graduated in Public Regulation and
Ph.D. (benchmarking in economic regulation). He has more than 40
publications worldwide. Presently he specializes in regulatory governance
and performance measurement. He has also worked as consultant.
Address(1): Instituto Superior Técnico, Technical University of Lisbon,
Av. Rovisco Pais, 1049-001 Lisbon, Portugal
Phone: +351 218418319, Fax: +351 218409884
E-mail: rcmar@civil.ist.utl.pt
The presence of market failures in the water and sewerage services might require the use of
economic regulation. The type of market failure and the high number of players underpin the use of
yardstick competition. This regulatory method is based on the comparison of the performance
results between companies from the same sector. This paper analyzes it in a theoretical sense and
discusses the empirical cases at work. It examines the yardstick model adopted in Portugal by the
regulator and suggests some changes to the current framework.
KEY WORDS: yardstick competition, benchmarking, sunshine regulation, water sector
Over the past years, a new model of organization and regulation of the water and sewerage services
(henceforth, WSS) has started to awake. This new paradigm, which begins to take shape in the
water sector in some countries and which is clearly established in other sectors, such as the one of
electricity, is the yardstick competition (hereafter, YC) model. The use of different kinds of YC is
connected with the application of benchmarking tools (statistical, econometric or others) by the
regulator (or by self-regulation) in the establishment of targets related either to the quality of service,
the tariff system or any other aspect of the WSS performance. The YC key-idea is based on the
performance results of the regulated company in comparison with the ones of other companies from
the same sector. Therefore, there is an incentive reorientation for the efficiency improvement of the
company under analysis by means of the information extracted from other companies. The
regulatory process becomes an artificial form of competition between the regulated companies
(MARQUES, 2005). The YC frameworks are diverse. They can either be compulsory or voluntary,
ranging from the simple act of publicizing and comparing the performance (sunshine regulation) to
more coercive forms closer to Shleifer’s model (SHLEIFER, 1985), including the efficient company
model. In the water sector, owing to its peculiar features, the introduction of benchmarking (in its
various forms) is often the major issue of its development. Unlike other public utilities, whose
liberalization is in progress, in the WSS it is not credible that this phenomenon can produce effects
in the short-run. So, the competition mechanisms can only rely on YC and on the regulation
capability to carry it on. The YC role in the WSS regulation is the core element of the analysis done
in this document. Its feasibility and implementation methodology are discussed for the water sector
both in Portugal and in other countries.
The modern definition of YC was developed in 1985 by Andrei Shleifer (SHLEIFER, 1985). Shleifer’s
model constitutes a very important landmark in regulation. Despite some limitations, the theory
underlying it was a basis for all the future developments of YC. A great part of the price cap or
revenue cap regulation methods that are employed today include the principles, to a larger or lesser
extent, of Shleifer’s model. This model presents a process of economic regulation based on the
comparison of costs obtained by companies operating in the same sector, where the target cost
level of each company can be determined, to which corresponds a socially efficient result. In this
regulatory scheme, the regulated price of each operator depends, therefore, on the costs of similar
operators under the same jurisdiction, leading to competition between the monopolistic operators,
although they act in different markets (regions). Hence, if an operator reduces the costs but its rivals
do not do it, there will be profits, conversely there will be losses. In the regulation of a given
operator, according to Shleifer, the average costs of the remaining operators from the same sector
will be used to determine the costs level it can attain. In fact, the model works, since an inefficient
operator can neither influence its own prices nor the value of the transference to be received.
Shleifer’s model is endowed with some difficulties that may jeopardize its implementation success,
in particular its heterogeneity, the collusion hypothesis, the presence of asymmetric information
(moral hazard and adverse selection), the underinvestment and the ratchet effect (SAGE, 1999).
These problems associated with asymmetric information can be minimized if the data envelopment
analysis (DEA) or other benchmarking technique is used instead of the averages mentioned
(BOGETOFT, 1997). The DEA based yardstick model developed by Peter Bogetoft consists of the
efficient cost determination of the operator under analysis, having as basis the performance
achieved by the other operators, allowing the former to keep a part of that difference as
compensation when the efficient cost is surpassed. Bogetoft and his colleagues have conceived
several models taking into account the different principles of the principal agent theory (AGRELL et
al., 2005). These models are similar to those used in the several countries in the electricity sector
regulation and that are either being studied or starting to be implemented in other countries in water
sector (e. g. Colombia).
The YC principles, based to a greater or lesser extent on Shleifer’s model, are present in diverse
regulatory processes around the world. Despite being increasing, the YC application in the scope of
the infrastructure services regulation, and in special of the WSS, with a configuration closer to the
one shaped by Shleifer, is still scarce. In the majority of the situations it is associated with the factor
X computation in the price cap and revenue cap formulas. However, there are other forms of YC,
such as the sunshine regulation, the efficient company model, the prospective payment budgeting,
the relative performance budgeting and the carrot regulation. The sunshine regulation approach can
be implemented alone or in complement with other regulatory techniques and it is founded on the
public display of the operator’s performance results and on their comparison with the remaining
operators from the same sector (MARQUES, 2005 and 2006a). The awareness of its performance is
obtained by pressure of different stakeholders. The sunshine regulation popularity in the water
sector is proved by its multiple applications (Portugal, Argentina, UK, Australia, Holland…). In the
efficient company model the regulator establishes the standard (efficient) behaviour for each
operator (BUSTOS and GALETOVIC, 2002). In this case there is no comparison with other
operators but with a theoretical operator that will assume current and future responsibilities and that
is designed to show exemplary performance. This model, original from Chile, where it is
implemented in almost all the infrastructure sectors (including water), has been extended to other
countries and it is used, for example, in the electricity regulation in Spain and Sweden. Prospective
payment budgeting relies on the concession of payments to the regulated operator, considering the
inputs (costs) of providing a given service, common to all the operators, supported by the average
costs from the previous year. If the operator is able to spend less than the forecasted it will obtain
profit, otherwise it will get losses. The USA and Italy are examples of the application of this
regulatory process to the health sector (SAGE, 1999). The relative performance budgeting is rooted
in the individual assessment of the operators’ outcomes. This method involves a kind of game where
the highest budgets come up as a reward to the best performances. This process can be found, for
instance in the funding of the scientific research in the UK (KOELMAN and VENNICKER, 2001). The
carrot regulation is based on the awarding of prizes, either monetary or not, to the operators with
best performances (BAGNOLI and BORENSTEIN, 1991). For example, the education system in
Israel follows this methodology.
As stressed above, in the WSS regulation the use of YC, although with a growing trend, is still little.
In this scope there are usually two YC approaches (MARQUES, 2005 and 2006a). The first,
generally stricter, relies on the benchmarking use to set the operators’ prices and tariffs (hereafter
called price YC). The kinds of benchmarking used (DEA, TFP, OLS and SFA) depend on the actors
and on the features of the countries involved. The second approach of YC application concerns
sunshine regulation, which comprises the comparison and public discussion of the operators’
performance. This light-handed kind of YC is often softer. Nevertheless, it does not mean that its
results are worse. In the WSS, sunshine regulation is being applied in several countries. The water
sector is highly fragmented, not much subject to regulation yet (by sector-specific regulator) and
usually its responsibility is ascribed to the municipalities. These features, along with the added value
it provides to the franchising in the quality of service regulation, justify the sunshine regulation
success within this sector. Besides, sunshine regulation can sometimes work as a first stage used
for the implementation of a second one whereby a more demanding and tighter regulatory process
takes place.
The water sector in Portugal
In Portugal, except for Lisbon, the WSS management responsibility belonged, until the 1990s,
exclusively to the municipalities. Only in 1993 was the private sector participation allowed. The
Executive Law No. 379/93 defined the legal regime of operation and management of the
multimunicipal and municipal systems of water intake, treatment and distribution for public
consumption and of wastewater collection, treatment and disposal. According to what is determined
by this law, the multimunicipal systems are those that provide “bulk” water to, at least, two
municipalities and that require a predominant investment by the State for reasons of national
interest. All the remaining structures are called municipal systems, even though they are managed
by municipal associations. This law includes the possibility of direct operation and management by
the State of the multimunicipal systems, and by the municipalities or their associations of the
municipal systems. It also allows the concession by the State (without competitive bidding) of the
operation and management of the multimunicipal systems to a public company or companies with a
major public capital shareholding, and the concession by the municipalities (if subject to public
tender) of the municipal systems management and operation to companies irrespective of capital
shareholder, or to users associations. In 1998, the Law No. 58 regulated the creation of municipal
companies, according to three frameworks, corresponding to only one municipality, more than one
municipality (intermunicipal company) and to one or more municipalities with a private partner
(mixed company) with minor shareholding, though the latter is subject to public tender.
The strategy delineated by the different Governments from the 1990s onwards led the organizational
model of the Portuguese water sector to be considered similar to the French model, despite some
particular features (MARQUES, 2006b). Firstly, there was unbundling, both in water and
wastewater. About 70 % of the municipalities import (or will import) water from other companies and
approximately 50 % of them export wastewater. Secondly, the State as entrepreneur emerged as
the main player not only in the “bulk” water supply (the unique until now) but also in direct water
distribution, competing with other private companies, particularly with the well-known multinational
companies. Finally, an industry-specific regulator for the water sector was established. Another
relevant issue, which characterized the Portuguese water sector in the last decade, was the growing
trend towards corporatization. Not only has private sector participation increased, with about 18 % of
the population in 2005 provided by private companies, but municipal companies have also been
spreading out. In 2005 there were already 13 municipal companies covering roughly 11 % of the
population. Table 1 shows the WSS market structure in Portugal at the end of 2005.
Notwithstanding the significant investment carried out over the last years, which markedly improved
the coverage level and made possible some optimization and integration of the existing systems, a
lot of work has yet to be done. Currently, even though some occasional problems of services
coverage might still occur (in particular sewage treatment), the main challenges faced by the water
sector, in Portugal, concern the management and operation efficiency and systems effectiveness
associated or not with a possible sector restructuring. High water losses, excessive staff in the urban
systems and lack of staff in the rural ones, inadequate tariff systems, inefficient assets management
and unsatisfactory customer service represent some of the problems to be discussed and solutions
must be found in the short-term. Moreover, if there are municipal systems in the coastal area and in
the great cities with an adequate size, there are others in the countryside which require
amalgamation in order to be sustainable.
Table 1: WSS market structure in Portugal (at the end of 2005)
Market structure Services (no.) Population (%)
Municipal service without autonomy 233 36.8
Municipal service with autonomy 31 28.6
Municipal company 13 10.9
State company 2 5.5
Private company 25 18.2
Municipal service without autonomy 248 48.0
Municipal service with autonomy 25 26.4
Municipal company 13 10.9
State company 0 0
Private company 18 14.7
The water sector regulation
In 1993, with the water sector opening to the private capital and with the strengthening of the private
operation and management formulas (multimunicipal systems), the Government decided that this
sector should be supervised by external entities. For that purpose, it created various entities that
never undertook functions. In 1996 one of the Government’s priorities would be to set a sectorspecific
regulatory authority for the WSS (and the solid waste). In 1997 the Institute for the
Regulation of Water and Waste (henceforth IRAR) was created and in 1998 its statutes were
approved. Its objectives were to ensure the quality of the services provided and to supervise the
financial equilibrium and sustainability of the sector under the terms of its statutes and the law. In
January 2006, IRAR had 46 workers and in 2005 it spent about €3,1 million (running costs), a
slightly lower value compared to the revenues coming from the operators’ payments according to
the existing consumption. Except for the control of the water quality for human consumption, the
WSS under municipalities’ management (municipal services without autonomy, municipal services
with autonomy and municipal companies) are not subject to IRAR’s intervention.
The plans of action of IRAR were conceived at the structural regulation level and at the operators’
behaviour level (conduct regulation) (BAPTISTA et al., 2003). In the first case, the functions refer to
the definition and consolidation of the market structure as well as to its strengthening. In the second,
the aspects that should be regulated deal with the behaviour of the operators, mostly with the prices
and the quality of service, that is, the so-called economic regulation. The regulation of prices and
investments is being performed having as basis the account and economic auditing of each operator
activities, enabling them to obtain a minimum rate of return (rooted in the rate of return regulation).
The quality of service regulation (and also the price regulation) use as main tool the comparison of a
performance indicators (PIs) set applied to each operator followed by its public display (sunshine
regulation). Figure 1 presents the regulatory model applied by IRAR.
Regulation model
Economic regulation
Quality of service
Performance comparison
publicly available
Conduct regulation
Structural regulation
Figure 1: IRAR regulatory model (BAPTISTA et al., 2003)
The role of the regulator
The role performed by IRAR has been widely restricted by its institutional design, particularly
because it is not an independent regulatory authority (MARQUES, 2005). The ambiguous bounds
between the State interests as producer and as regulator have been putting at risk the regulation
effectiveness. IRAR does not have many tools that might enable it to act effectively. For example, its
powers are weak concerning the enactment of regulations and limited with regard to the execution of
penalties. The arbitration and conflict resolution are also restrained by lack of independency. IRAR,
as stressed above, does not have economic regulation functions regarding the operators under
municipalities’ management. Besides, even with reference to the municipal concessionary
companies, IRAR does not have competences to set prices and tariffs, which are defined in the
concession contract between the municipality and the operator, unless the economic and financial
balance of the concession is at risk.
One of the main objectives IRAR is trying to perform, at least in this phase, is the quality of service
regulation by means of the sunshine approach. IRAR developed a set of PIs for the regulated
activities of water, wastewater and solid waste. They are intended to be published annually and the
operators who have a less good performance are expected to be “embarrassed” and, as a result, to
correct the deviations presented. It should be noticed that sunshine regulation does not fix tariffs and
its coercive power is, almost always, limited. However, the exposition and the public discussion of
the operator’s behaviour produces very positive effects as it introduces competitiveness among
operators and leads to the gradual performance increase of the whole sector. Sunshine regulation is
especially directed to the quality of service control, chiefly when the rights and obligations of the
operators are defined in a contract. It also appears as a transition phase when the intention is to
move towards a stricter and more intervening regulatory process or when the sector is very
fragmented (MARQUES, 2005). These three reasons justify the option for sunshine regulation in
Portugal. The year 2005 corresponds to the first year of the regulatory model implementation,
therefore being impossible to make a rigorous assessment of its application. Table 2 presents the
water supply PIs specified by IRAR for the “bulk” water supply and direct water distribution systems
alone and for both of them managed simultaneously.
Table 2: PIs for water supply proposed by IRAR (ALEGRE et al., 2004)
PIs “Bulk supply” “Direct distribution” Both
Protection of the use interests
Use service accessibility
Service coverage (%) 􀁄 􀁄 􀁄
Average water charges (€/m3) 􀁄 􀁄 􀁄
Quality of service supplied to users
Service interruptions (n.º 1000 sc/year) 􀁄 􀁄 􀁄
Water tests performed (%) 􀁄 􀁄 􀁄
Quality of supplied water (%) 􀁄 􀁄 􀁄
Answers to written complaints (%) 􀁄 􀁄 􀁄
Sustainability of the operator
Economical and financial sustainability
Operating cost coverage ratio (-) 􀁄 􀁄 􀁄
Unit running costs (€/m3) 􀁄 􀁄 􀁄
Solvency ratio (-) 􀁄 􀁄 􀁄
Non-revenue water (%) 􀁄 􀁄 􀁄
Infrastructural sustainability
Fulfilment of the water intake licensing (%) 􀁄 – 􀁄
Treatment utilization (%) 􀁄 – 􀁄
Transm. And distrib. storage capacity (days) 􀁄 􀁄 􀁄
Mains rehabilitation (%/year) 􀁄 􀁄 􀁄
Service connection (SC) rehabilitation (%/year) – 􀁄 􀁄
Operational sustainability
Mains failures (n.º/100km/year) 􀁄 􀁄 􀁄
Human resource sustainability
Employees (no./100km/year) or (no./1000 SC) 􀁄 􀁄 􀁄
Environmental sustainability
Utilization efficiency of water resources (%) 􀁄 􀁄 􀁄
Use efficiency of energy (kWh/m3/100m) 􀁄 􀁄 􀁄
Final destination of sludge (%) 􀁄 – 􀁄
Evaluation of the regulatory model of IRAR
The option for the YC use in Portugal is justified by diverse reasons, such as the existing high
inefficiency levels, the Portuguese water sector market structure, the politicians’ interference in the
WSS management and the lack of transparency revealed by some operators (MARQUES, 2005 and
2006b). As previously mentioned, sunshine regulation is the backbone of the Portuguese regulatory
model. The adoption of this approach is understood if one considers the regulator’s responsibilities
(only for the concessionary services either with “bulk” water supply or direct water distribution), the
existence of a contractual regulation (franchising) for these operators and the sector’s
fragmentation. So, I believe it is impossible to implement a regime similar to the one of OFWAT in
the UK in the short-term with the current market structure, and much less one closer to the Chilean
model of the efficient company. However, great results cannot be expected with sunshine regulation,
especially regarding the economic efficiency if, on the one hand, it will only be based on PIs and if,
on the other, it just comprises the concessionary companies.
The PIs are computed easily and have a transparent meaning. Nonetheless, they can lead to
misleading conclusions when taken by themselves. These indicators assess only one aspect of
productivity as they rely on a single input and on a single output. Hence, from a global viewpoint,
when there is a more or less complex combination of inputs and outputs able to substitute one
another, its usefulness can be slight or even harmful. Table 3 provides evidence of that situation.
Table 3: PIs for the year 2001 of 4 Portuguese WSS of similar size (MARQUES, 2005)
WSS Staff/customer
(no. 10-3 cu.) Ranking Staff/volume
(no. 10-6 m3) Ranking Staff/mains length
(no. 10-1 km) Ranking
Leiria 3.60 2 30.48 4 1.84 2
Setúbal 4.19 4 29.36 1 5.98 4
Viana 3.43 1 30.22 3 2.30 3
C. Branco 3.69 3 29.91 2 1.12 1
This does not mean that the PIs should not be computed and publicized. This activity is very
important, in particular to promote transparency and with regard to the quality of service regulation,
mainly aiming at analyzing very specific aspects (e. g. complaints, waiting time,…). In any case, the
conclusions must be carefully assessed and never taken out of context as these indicators are only
partial measures of productivity. For example, the PI failures per 100 km of mains length can double
its value if an urban system is considered rather than a rural one and even in this situation the
former has a better performance than the latter. The WSS can be classified into urban, semi-urban
and rural if the customers’ density is superior to 125 customers per km of mains length, between 50
and 125 and inferior to 50, respectively (MARQUES and MONTEIRO, 2001). These values can lead
the ordinary citizen or customer to take wrong conclusions. Total macrobenchmarking methods,
such as TFP, DEA and SFA, which entail multiple inputs and outputs and that, for this reason, offer
a better representation of reality, should also be applied to provide incentives to the WSS efficiency
and productivity improvement (MARQUES, 2006a and b). Sometimes it is forgotten that the best
way of protecting the customers is undoubtedly to turn the operators into efficient and productive
and this should be the regulators’ foremost goal.
From another perspective, the publication of PIs aims at the performance comparison between the
WSS. However, the number of WSS operating in this sector under the jurisdiction of IRAR, despite
being already significant, is divergent in its integration level, preventing an effective comparison to
take place due to its heterogeneity. It entails companies whose purpose is the “bulk” water supply
(or wastewater), others with the task of direct water distribution, others that do both of them
simultaneously and others that are also responsible for the wastewater. In short, there is a panoply
of cases that make the implementation of benchmarking impracticable (“apples with apples”
comparison). Moreover, part of the operators that had privatized their services did not do it for an
ideological option or for more swiftness and efficiency of the private sector, but rather because they
had serious problems without easy solution (for example, reduced coverage levels) or, in other
words, they were victims of the so-called scissors effect, which in practical terms would lead to the
existence of three or four operators by each group with a minimum of homogeneity. At last, it should
be noticed that concession contracts are very dissimilar. For instance, in some cases the
concessionary is responsible for the rehabilitation, but in other cases it isn’t. The worst performance
is not often responsibility of the operator but of the municipality that does not fulfil its obligations. The
operator can be unfairly penalized. Thus, in order that YC will have further positive effects, the
scope of action of IRAR needs to be extended to the operators under municipal management. In this
way, as there are a high number of players, they can be grouped by clusters, avoiding the
justification for the poor or outstanding performances through the WSS diversity.
In a recent study a model of YC was suggested for Portugal (MARQUES, 2006b) with some
similarities to the Norwegian case-study presented, in particular with regard to the DEA technique
use in the WSS efficiency calculation. In the methodology proposed, in a first phase it would only be
applied in the sunshine approach so that the inefficient WSS could get closer to the efficient frontier,
in a second phase this approach would be complemented by a carrot and stick policy (regulation)
and in a third phase, after recovering the inefficiency gap, an automatic procedure of tariff
determination identical to the Norwegian scheme would be used. At this point, DEA would be
completed by statistical inference based on the bootstrap re-sampling methodology. Figure 2
illustrates the model proposed.
Sunshine regulation
Sunshine YC with “carrot”
Gap overcome?
Yes No
Price YC Sunshine YC with “carrot
and stick” policy
Gap overcome?
Yes No
Price YC Sunshine YC with “carrot
and stick” policy
Price YC
Figure 2: Regulatory model proposed for the WSS in Portugal (MARQUES, 2005 and 2006b)
YC consists in the regulation of an operator having as basis the performance evaluation of the
remaining operators from the same sector. This regulatory model rewards the operators that cut the
costs below the average (or of outstanding performance) and penalizes those with higher costs (or
inferior performance).
The benefits of using YC are well visible in the empirical cases from the around the world as it is
proved by the cost reduction and the performance improvement, even when the YC approaches are
theoretically less powerful, as sunshine regulation. In this case, it takes longer to reach the
objectives defined. Its impact on efficiency and productivity is also lesser and the outcomes can be
far from the desired. However, the adoption of regulatory processes based on price YC, besides the
assumptions inherent to their implementation, should not forget some basic principles, such as not
being too much demanding or the transparency and the discretionarity reduction.
In Portugal, the WSS regulation is carried out by IRAR. This regulatory authority has limited powers
and weak tools and it is not independent, which reduces the regulation effectiveness. IRAR adopted
the YC sunshine approach as its key regulatory instrument. The YC implementation in Portugal is
justified by several reasons as the inefficiency levels, the market structure of the Portuguese water
sector, the confusion between politics and the WSS management and the lack of transparency
revealed by some operators. The regulatory model comprises the determination, comparison and
public display of PIs regarding the regulated activities. The PIs application leads to good outcomes
as far as the quality of service improvement is concerned but to not so good effects on the issue of
economic efficiency enhancement. In addition, in Portugal only a small number of operators are
subject to the intervention of IRAR. So, its heterogeneity will not allow the accomplishment of very
satisfactory results.
Although it is recognized that the PIs publication might be useful, there are other competing or
complementary techniques, such as DEA, that can be applied in sunshine regulation. Besides being
more advantageous in some aspects, these techniques are superior from the theoretical point of
view. According to its benefits, the DEA technique is suggested as the main regulatory tool to be
adopted. After improving the information quality and after recovering some inefficiency of the
Portuguese WSS, it is possible to go beyond the sunshine phase and consider a price YC scheme,
similar to the dynamic model of Bogetoft.
1. AGRELL, P., BOGETOFT, P., TIND, J. Dynamic DEA and yardstick regulation in Scandinavian
electricity distribution. Journal of Productivity Analysis, v.23, n.2, p.173-201, 2005.
2. ALEGRE, H., HIRNER, W., BAPTISTA, J., PARENA, R. Indicadores de desempenho para
serviços de abastecimento de água. National Laboratory of Civil Engineering and Institute for the
Regulation of Water and Waste, Lisbon, 2004.
3. BAGNOLI, M., BORENSTEIN, S. Carrot and yardstick regulation: enhancing market
performance with output prizes. Journal of Regulatory Economics, v.3, n.2, p.115-136, 1991.
4. BAPTISTA, J., PÁSSARO, D., SANTOS, R. As linhas estratégicas do modelo de regulação a
implementar pelo Instituto Regulador de Águas e Resíduos. Institute for the Regulation of Water
and Waste, Lisbon, 2003.
5. BOGETOFT, P. DEA – based yardstick competition: the optimality of best practice regulation.
Annals of Operations Research,v.73, n.1, p.277-298, 1997.
6. BUSTOS, A., GALETOVIC, A. Monopoly Regulation, Chilean Style: the Efficient Firm Standard
in Theory and Practice. CEA Working Paper, 2002
7. KOELMAN, J., VENNIKER, R. Public funding of academic research: the research assessment
exercise of the UK. In Higher Education Reform: Getting the Incentives Right. The Hague:
Netherlands Bureau for Economic Policy Analysis and Center for Higher Education Policy
Studies, 2001.
8. MARQUES, R. A regulação de serviços públicos. Edições Sílabo, Lisbon, 2005.
9. MARQUES, R. Performance benchmarking in water and sewerage services regulation:
Principles and experiences. Water Utility Management International, v.1, n.2, p.16-21, 2006a.
10. MARQUES, R. A yardstick competition model for Portuguese water and sewerage services
regulation. Utilities Policy, v.14, n.3, p.175-184, 2006b.
11. MARQUES, R., MONTEIRO, A. Application of performance indicators in water utilities
management – a case-study in Portugal. Water Science & Technology, v.44, n.2/3, p. 95-102,
12. SAGE, E. La concurrence par comparaison (“Yardstick Competition”) – Théorie et applications –
Une proposition pour le secteur de l’eau en France. Ph.D. Thesis, Université Paris IX-Dauphine,
13. SHLEIFER, A. A theory of yardstick competition. Rand Journal of Economics, v.6, n.3, p. 319-
327, 1985.



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