Spurious and Symbolic Diffusion of IndependentRegulatory Agencies in Western Europe
Independent regulatory agencies (IRAs) have become the most widespread form of
organisation for regulatory policies in Western Europe. Their pattern of emergence
suggests that a diffusion process may have been at work, namely a process where
the decisions to set up IRAs have not been independent. This paper investigates
whether the spread of IRAs is related to diffusion. It draws a distinction between
spurious diffusion, which is due to the concomitant reaction of independent actors
to similar pressures, and interdependent diffusion, where actors are influenced by
the behaviour of others. Eight mechanisms of interdependent diffusion are
discussed, which can be differentiated on the basis of how they are related to the
improvement of the problem-solving capacity of actors. While learning and
regulatory interdependence assume that actors are sensitive to the behaviour of
other because it can make them better off, symbolic diffusion stresses that policies
and institutions can be diffused irrespective from the functions they perform. The
empirical analysis relies on an original data set comprising information for
regulators in seven regulatory domains (telecoms, electricity, financial markets,
competition, food safety, pharmaceuticals, and environment) in seventeen countries
(EU member states plus Switzerland and Norway). It does not examine all
mechanisms but, more modestly, aims at determining, through an event history
model, the role of spurious and symbolic diffusion. Results show that both have
Paper for presentation at the workshop "The Internationalization of Regulatory
Reforms", Center for the Study of Law and Society, University of California at Berkeley,
During the last fifteen years or so, independent regulatory agencies have been created
in all West European countries and most regulatory domains. Figures 1 and 2 show the
trend in economic and social regulation2 respectively. The number of IRAs has increased
very sharply since about the mid-80s for economic regulation and the early 90s for social
regulation. In some domains, such as telecoms, all countries have set up an IRA. At first
this trend strikes as surprising, but a closer look reveals that it is all but exceptional. In
fact, many phenomena could be described by a similar curve. These include the spread
of technological innovations, diseases, social actions such as joining a strike or a riot,
and other phenomena commonly regarded as being subject to diffusion. Indeed, this
strongly suggests that a diffusion process may be at work behind the creation of IRAs.
The purpose of this paper is to examine this hypothesis by differentiating between
spurious and symbolic diffusion. Spurious diffusion is simply due to the concomitant
reaction of independent actors to similar functional pressures. In symbolic diffusion, on
the other hand, actors are influenced by the behaviour of others. More specifically,
actors are more inclined to set up an IRA if others have already been so, but, unlike in
learning for example, this happens independently from the problem-solving properties
of IRAs. As stressed in the sociological institutionalist literature, the set-up of IRAs may
occur because they have become taken-for-granted as an appropriate way to organise
regulation, or because they supply legitimacy to other policy choices. Schematically, the
symbolic diffusion hypothesis suggests that the decision to establish an IRA at time t
should be somehow (positively) related to the number of IRAs existing at time t-1.
The paper is structured as follows. I will first try to make clear which aspects of
diffusion I consider in the analysis, and which others I leave out. To this end, I develop a
1 I wish to thank Victor Lapuente Giné, David Levi-Faur and Covadonga Meseguer for their comments ona previous version of this paper. I also gratefully acknowledge the generous financial support of theFondation du 450ème anniversaire de l’Université de Lausanne. 2 Regulation is conventionally termed "economic" when it deals with the price, entry, exit and service ofan industry, while it is termed "social" when it concerns non-economic issues such as safety and health(Meier 1985: 3).
tentative typology of diffusion mechanisms based on the existing literature, to which I
add a dimension often neglected, namely symbolic diffusion. In particular, the typology
differentiates between spurious diffusion and interdependent diffusion, of which
symbolic diffusion is one component, along with learning and regulatory
interdependence. In the second part I carry out an empirical analysis where I try to
determine to what extent the spread of IRAs has been driven by spurious and symbolic
diffusion. In a first step IRA creations are studied at the aggregate level through a
Poisson model; in a second I examine individual IRA creations through event history
analysis. The analysis is based on an original data set comprising information for
regulators in the seven regulatory domains shown in figures 1 and 2 and seventeen
European countries (EU member states plus Switzerland and Norway). Results show
that there are good reasons to believe that both spurious and symbolic diffusion explain
The political science literature on diffusion is rapidly growing and, though a unified
approach does not exist, several typologies have been developed. In this section I put
forward my own classification. Although I hope that it can add something to the
existing discussions, the primary goal is to make clear what is included and, more
importantly still, what is left out in the present analysis.
As Eyestone stresses, "any pattern of successive adoptions of a policy innovation can
be called diffusion" (Eyestone 1977: 441). The challenge is to discriminate diffusion
processes where policy choices of given actors are affected by the prior choices of other
actors from processes where the outcome is driven by the reaction of independent actors
to similar functional pressures. Only the former can be characterised as diffusion, while
the latter should be seen as spurious diffusion. This view is consistent with the argument
of Dobbin, Garrett and Simmons (2003), who distinguish between diffusion and a "null
hypothesis" where the spread of policies can be explained by the independent behaviour
of actors. In contrast to this formulation, the concept of spurious diffusion explicitly
acknowledges that actors behaving independently can, under some conditions, lead to a
pattern of policy adoptions with the same features as an interdependent diffusion
Spurious diffusion of IRAs may derive from the roughly concomitant emergence of
functional pressures for delegation, and from governments' response to it. The logic is
similar to that of spurious diffusion of central banks. The main rationale of delegating
powers to independent central banks is that they are an effective means to keep inflation
low. Evidence that governments set-up independent central banks after experiencing
high inflation would indicate the presence of spurious diffusion. Interestingly, Castro
and McNamara (2003) find that inflation has no effect on the decision to grant
independence to central banks. In the case of IRAs, spurious diffusion could be driven
by the need to achieve credible commitment capacity and/or the attempt to cope with
political uncertainty problems. Firstly, when opening markets to competition, as in the
case of telecom or electricity, governments need to be able to convince investors that the
regulation of the market will not be biased in favour of the former state-owned
incumbent (Levy and Spiller 1994). By delegating regulatory powers to IRAs,
governments can improve the credibility of this commitment to fair regulation (Majone
1997, 2001). The reason why this is a particularly strong explanation is that, unlike most
others, it addresses the really original feature of IRAs, namely their independence from
politics. A second explanation that goes in the same direction is the political uncertainty
hypothesis (Moe 1990; de Figueiredo 2002), which claims that politicians insulate policy
from politics to make the former last beyond their term of office. In reason of the
democratic process, political property right over policy are always uncertain. New
governments can undo what old ones have done. Delegation to independent agencies is
a means to make this more difficult. As there is evidence that both credibility and
political uncertainty matter in explaining cross-sectional differences in delegation to
IRAs (Gilardi 2002, 2003), these two arguments are good candidates as causes of
Turning to non-spurious diffusion, the most prominent scholars agree that it is driven
by the interdependence of actors, but there is no clear consensus on its different sub-
types. Dobbin, Garrett and Simmons (2003) stress the role of dominant actors, economic
competition, rational learning, and social emulation. Weyland (2002) emphasises
external pressure, rational learning, cognitive heuristic (bounded learning), and
symbolic imitation. Simmons and Elkins (n.d.) differentiate between economic
competition, learning (through communication channels), and cultural emulation. Brune
and Garrett (2000) similarly speak of competitive emulation, learning, and social
emulation. On the basis of these studies, I have tried to develop my own typology. As
stressed above, the main goal is to clarify what is included in the empirical analysis, and
what is left out, though hopefully the discussion also supplies a useful synthetic view of
Figure 2 presents the typology. It is explicitly acknowledged that diffusion proper
occurs only when actos behave interdependently. When this does not occur, a diffusion-
like pattern of adoptions can still emerge, notably if actors react to similar functional
pressures, but in this case diffusion should be considered spurious. One of the main
tasks of empirical analyses, as stressed by Dobbin, Garrett and Simmons (2003), is to
assess if, and to what extent, diffusion is non-spurious. The second task, if
interdependent diffusion is found, is to determine which mechanism is at the root of the
diffusion process. Neither task is easy. In effect, the exercise is plagued by the problem
of observational equivalence, as all mechanisms, including spurious diffusion, lead to
the same outcome (or at least to very similar outcomes).
In my view, the main distinction is between diffusion mechanisms where problem-
solving is the primary rationale for action, and, on the other hand, those where policies
spread irrespectively from their problem-solving capacity. In the first category we find
learning, which can be fully rational or only boundedly so. Rational learning (mechanism1) is best conceptualised in bayesian terms (Meseguer 2002; Breen 1999). Here,
governments (as well as other actors) are assumed to act after updating their beliefs
about the benefits of a given policy by looking at the experience of others. For example,
the mean and variance of relevant outcomes can supply information on the effects of a
given policy, and this information can be used to update prior beliefs and eventually
Bounded learning (mechanism 2), on the other hand, is a bounded rationality version
of bayesian learning (Weyland 2002). In this case, actors try to gather relevant
information from the observation of the behaviour of others, but, rather than on
bayesian updating, they rely on "cognitive shortcuts" such as representativeness,
availability and anchoring3 (Tversky and Kahneman 1974; McDermott 2001; Weyland
2002). Learning here can be much less effective than in the bayesian view. Actors do try
to get new information from the experience of others, but use cognitive shortcuts rather
than Bayes' rule to update their beliefs. An implication is that while in bayesian learning
all relevant information is used to rationally update beliefs, in bounded learning only
some relevant information is gathered and used through such cognitive shortcuts as
representativeness, availability and anchoring. Brune and Garrett's (2000) and Dobbin,
Garrett and Simmons' (2003) "social emulation" and Simmons and Elkins' (n.d.) "cultural
emulation", in spite of their names, belong to bounded learning. As the authors make
clear, in fact, these mechanisms involve information-gathering from a peer group, and
are thus an imperfect (i.e. not fully rational, i.e. non-bayesian) way to learn about the
In cooperative and competitive regulatory interdependence (Lazer 2001), on the other
hand, the logic of diffusion remains problem-solving oriented, but is not grounded in
the wish or need of actors to gather new relevant information that can help them in
making better policy choices. Under cooperative interdependence (mechanism 4),
diffusion is driven by the benefits that follow from having compatible policies, and
under competitive interdependence (mechanism 3) by strategic responses to the
3 Representativeness refers to the process through which people link phenomena by evaluating the degreeto which one is representative of the other, that is by the degree to which one resembles the other. Forexample, it has been demonstrated that people assess the probability that a person is engaged in aparticular occupation by determining the degree to which his/her description, or appearance,corresponds to the stereotype of the occupation. This method can lead to serious misevaluation because itneglects several factors that affect the objective probability, such as prior probability, sample size, thereliability of the evidence (Tversky and Kahneman 1974). This heuristic device is incompatible withbayesian learning, where, for example, sample size matters in the formation of posterior beliefs (Meseguer2002: 27). Secondly, availability refers to the process through which "people assess the frequency of a classor the probability of an event by the ease with which instances or occurrences can be brought to mind"(Tversky and Kahneman 1974: 1127). An example would be determining the likelihood of getting cancerby recalling the number of cases of cancer among acquaintances. Availability also means that theevaluation of the risk of an activity, for example, is affected by the ease with which its dangers can beimagined. This process can introduce several biases in judgements, because instances which are moreeasily retrievable or imaginable, for example because of familiarity or salience, tend to be perceived asmore numerous or more frequent. This heuristic device is at odds with bayesian learning, which assumesa use of information consistent with statistical laws. Anchoring, finally, is the process through whichpeople make estimates by adjusting an initial value. The adjustment will typically be insufficient, meaningthat the estimate will remain anchored to the initial value, even when this does not convey relevantinformation. This means that external information has a bigger impact on judgement than it should.
behaviour of competitors. The latter mechanism is thus analogous to Brune and
Garrett's (2000) "competitive emulation", Dobbin, Garrett and Simmons' (2003)
"economic competition", and to Simmons and Elkins' (n.d.) "diffusion among economic
competitors", while the former is not present in these studies.
The second broad category of diffusion mechanisms is characterised by the fact that
behaviour is not oriented towards problem solving. In coercive and normative
isomorphism (DiMaggio and Powell 1991), the spread of organisations and policies
depends much more on their advocacy by powerful or authoritative actors than on the
problems they permit to solve4. Coercive isomorphism (mechanism 5) results from the
presence of pressures, both formal and informal, exerted on organisations by other
organisations upon which they depend. This mechanisms includes then Dobbin, Garrett
and Simmons' (2003) "dominant actors" that, through power relations, can impose the
adoption of policies and thus contribute to their diffusion. Normative isomorphism
(mechanism 6), on the other hand, arises from processes of professionalisation and
socialisation within networks, where persuasion may occur through the development of
conceptual model that gain authority through their advocacy by prominent actors
The last two mechanisms of diffusion are related to symbolic imitation, and will be at
the centre of the empirical analysis. First, the set up of an organisation, or the adoption
of a policy, can be a ceremony intended to provide legitimacy to certain decisions by
diverting the attention from more substantial concerns (mechanism 7) (Meyer and Rowan
1977: 349). In the case of IRAs, governments may create independent regulators so as to
legitimate other decisions, such as liberalisation of utilities. As IRAs become valued by
the broader institutional environment (which includes norms and values), establish
them may enhance the legitimacy of certain policy choices. Second, over time some
organisational forms can become “taken for granted”, while others disappear from the
“domain of possible” (mechanism 8) (Hannan and Carroll 1992; Baum and Oliver 1992).
In this perspective, organisations are not established as legitimation devices, but simply
because they have become the normal or obvious thing to do in given contexts, while
other options are not even considered. Over time, some policies become the most
Again, this is different from bayesian learning, where the use of the new information, which is used totransform priors into posteriors, does not lead to bias in beliefs.
widespread. As a result, potential new adopters will tend to see those policies as the
natural or obvious way to deal with a given problem, and tend to unconsciously exclude
other solutions that could also be viable in principle. The outcome of this process is that
new adopters tend to choose the dominant policy or organisation, which then becomes
even more dominant. Technically, an organisational form that reaches this stage is said
to be "taken-for-granted", and it has been argued that "taken-for-grantedness" is directly
related to the total number of similar organisations that exist. The main hypothesis that
is derived from these arguments is that the relationship between the number of existing
organisations and the number of new adoptions has an inverted-U shape: the impact of
the former on new adoptions is at first positive (because of taken-for-grantedness), but
then becomes negative (because of the increased competition between organisations).
This pattern has been tested empirically and is extremely robust. It can be found in a
wide range of organisations, including public schools (Rowan 1982), the multidivisional
form of management structure (Fligstein 1985), health care organisations (Ruef 2000),
newspapers (Carroll and Hannan 1989), and banks (Ranger-Moore et al. 1991), just to
To sum up, I suggest that interdependent (i.e. non-spurious) diffusion mechanisms
can be divided in two main categories. In the first, the behaviour of actors is problem-
solving oriented, and can be found mechanisms such as rational (Bayesian) and
bounded learning, and competitive and cooperative interdependence. In the second,
policies are diffused independently from their problem-solving value. The mechanisms
are here coercive and normative isomorphism, as well as symbolic diffusion, which can
be divided into legitimacy-seeking and taken-for-grantedness. In the next section I
present the hypotheses that will drive the empirical analysis.
I will not be able to examine all eight diffusion mechanisms. Rather, I will try to
determine the relative importance of spurious and symbolic diffusion (mechanisms 7
and 8) in the spread of IRAs. There are several reasons to focus on symbolic imitation.
4 In the third form of isomorphism, mimetic isomorphism, copying occurs because of uncertainty. It can
The first is that, while it is central in sociology, it has been neglected in political science
studies of diffusion. As mentioned in section 2, when political scientists speak of social
or cultural emulation, they actually mean a process of bounded learning. Secondly,
some mechanism, seem less relevant for IRAs than for policies such as foreign economic
policy, privatisation or welfare state reform. Learning, both rational and bounded, are
likely to very important for IRAs, but the difficulties of an empirical analysis are
daunting at this stage. For Bayesian learning, it is crucial to identify clearly (and
measure) the outcomes that governments observe in order to update their preferences.
This is far from straightforward given that I compare not only countries but also sectors.
For bounded learning, it should be at the very least determined which is the “peer
group”, or group of reference, not only for every country but also for every sector. In
effect, it is very much possible that peers are not the same in all sectors. For example,
governments could look at the UK for utilities regulation, but at Scandinavian countries
for environmental policy. In addition, the homogeneity of the countries under enquiry
means that meaningful geographical groups can less easily be identified than in global
studies (e.g. Brune and Garrett 2000; Simmons and Elkins n.d.). Finally, normative
isomorphism is both interesting and problematic. In effect, it is interesting to note that
networks of regulators have been created, and it is very much plausible that within
them a common professional culture is created that can eventually lead to isomorphism.
However, the problem is that in most cases regulators can enter these networks only if
they are IRAs. Moreover, most such networks are more recent than many IRAs.
Coercive isomorphism is also problematic. Two institutions (or “dominant actors”) can
potentially have led to coercive isomorphism for IRAs, namely the OECD and the EU.
The OECD, however, has only recently become interested in the promotion of IRAs, and
it has not yet issued explicit recommendations in this direction. The impact of the EU,
on the other hand, is partly taken into account in the analysis, as explained below.
In the empirical analysis I will then simply try to determine to what extent the spread
of IRAs is due to spurious diffusion, and to what extent to symbolic diffusion. The
H1: privatisation and liberalisation have a positive impact on the likelihood that an
IRA is created (credibility hypothesis, spurious diffusion);
be conceptualised as a form of bounded learning, and is thus not treated separately here.
H2: when controlling for privatisation and liberalisation, the likelihood that an IRA is
created is more likely in competition and financial markets than in other regulatory
domains (credibility hypothesis, spurious diffusion);
H3: the risk for a government of being replaced by a coalition with different
preferences has a positive impact on the likelihood of IRA creation (political
uncertainty hypothesis, spurious diffusion)
H4: the impact of replacement risk depends on whether this high replacement risk is
common or exceptional in a given country; its impact is bigger when political
uncertainty is unusual (see Gilardi 2003) (political uncertainty, spurious diffusion);
H5: veto players increase policy stability (Tsebelis 2002) and are thus a functional
equivalent for delegation for both credibility and political uncertainty. Thus, veto
players mediate the impact of privatisation, liberalisation, competition and financial
markets regulation, and replacement risk (spurious diffusion);
H6: the number of IRAs existing at time t-1 have a positive impact on the likelihood
that an IRA is created at time t (symbolic diffusion);
H7: the number of IRAs existing at time t-1 interacts with functional pressures for the
creation of IRAs (H1, H2, H3) and enhances their positive impact on the likelihood
that an IRA is created (symbolic diffusion);
H8: EU regulations requiring the establishment of separate regulators have a positive
impact on the likelihood that an IRA is created (coercive isomorphism).
I will examine the diffusion of IRAs in two steps. Firstly, I follow the methods used in
the population ecology literature and analyse the pattern of creation of IRAs at the
macro level, by focusing on the evolution of the population of IRAs disaggregated into
sub-populations (i.e. regulatory domains). This will constitute a first test of the relevance
of symbolic diffusion, but some limitations will be discussed that make this test
insufficient. In the second step, then, I shift to the micro level to examine individual IRA
creations through an event history analysis. In both cases, the analysis5 relies on an
5 The variables, their operationalisation and source are summarised in Appendix 1.
original data set comprising information for regulators in seven regulatory domains
(telecom, electricity, financial markets, competition, food safety, pharmaceuticals, and
environment) in seventeen countries (EU member states plus Norway and Switzerland).
In the population ecology literature (Hannan and Carroll 1992; Baum and Oliver
1992), the evolution of organisational populations is analysed by looking at how many
new organisations of the same type are created in a given period of time. When sub-
types of organisations can be identified, the analysis is carried out at the sub-population
level. In this first step, I embrace this technique and examine how many new IRAs are
created each year in each of the seven regulatory domains covered by my database. The
dependent variable consists of event counts, and this kind of data can be best analysed
through Poisson regression models (King 1988; Greene 2003: 740-752). The model used
E(yi|xi) = exp(βX),
where E(yi|xi) is the expected number of events per period, conditional on the
independent variables, and βX is a vector of the regression coefficients and the
Table 1 shows the results. The three models investigate the pattern of emergence of
IRAs in Western Europe at different levels of analysis. The first model is the most
general and undifferentiated. It does not differentiate between regulatory domains and
studies only the overall IRAs population. The second model divides the overall
population in two subpopulations by considering social and economic regulation
domains separately, but without differentiating between, for example, electricity and
financial markets, or food safety and environment. In the first model, the number of
IRAs is scarcely significant. In the second, the overall number of IRAs has significant
positive first-order and negative second-order effects, as predicted by the theory. The
number of IRAs at the regulatory type level, on the other hand, is not significant.
Model 3 tests the main argument of this first step of the analysis, namely that the
creation of IRAs in different regulatory domains is affected by the number of existing
IRAs. It can be seen that number of IRAs at both the overall and regulatory domain level
are significant in the expected direction, namely with positive first-order and a negative
second-order effect, but not at the regulatory type level. Economic regulation, the
dummy used to account for functional pressures for the creation of IRAs, is significant
and positive. These results show that the number of IRAs has an impact at both the
overall and the regulatory domain level, but not at the regulatory type level. In other
words, the creation of an IRA for competition policy, for example, is affected by the
existence of other IRAs in the same domain, but also by the existence of IRAs in general.
It does not matter however, whether existing IRAs outside the specific regulatory
domain are of the same regulatory type (i.e. economic or social regulation). For the
creation of an IRA for competition policy, the existence of IRAs for financial markets or
food safety matter equally. Another result is that, in spite of the relevance of the number
of IRAs, functional pressures also play a role in explaining the creation of IRAs. In effect,
economic regulation, where credibility problems are more acute than in social
regulation and thus the incentives to delegate regulatory competencies to IRAs are
higher (Gilardi 2002), is positively associated to the creation of IRAs after controlling for
the impact of the number of existing IRAs. Symbolic diffusion seems to be at work, but
Figure 4 depicts graphically the relationship between the total number of IRAs and
the creation of new IRAs6. It can be seen that, as predicted by the theory, the relationship
is non-monotonic. When few IRAs exist, the effect of the total number of IRAs on new
creations is relatively small, but grows quickly up to the point where the fact that many
of the regulators have become IRAs reduces the likelihood that new IRAs are created. A
second point of interest in Figure 2 is the difference between the curves for economic
6 To the values on the y axis, representing predicted foundings, should not be attributed too muchimportance as their value depends strongly on the values at which the independent variables not includedin the graph are kept constant.
and social regulation. The curve for social regulation has always lower values than that
for economic regulation. This reflects the fact that functional pressures for delegation,
notably in terms of credibility, are different between the two types of regulatory
This result strongly suggests that a symbolic diffusion process at least partly explains
the pattern of creation of IRAs. However, the methods used in this first step of the
analysis have several problems that limit its usefulness. The first is that the S-shaped
pattern of diffusion shown in Figure 1 can be identified in countless other domains,
most of which have nothing to do with politics. Ironically, the same pattern has been
followed by the diffusion of research on diffusion (Rogers 1995: 45). It can thus be
suspected that the inverted-U relationship between the number of existing IRAs and
new IRA creations (or other adoptions) is simply due to the “inescapable mathematics of
musical chairs” (Schelling 1978) that characterises many social phenomena, i.e. the fact
that they are true by definition. The second is that the focus on whole populations (or
sub-populations) prevents the researcher from controlling for many potentially
important variables. In the case of IRAs, for example, one cannot account for variables
that vary cross-nationally. It is also difficult to integrate time-varying explanations in a
consistent way, because they typically vary also cross-nationally. The clearest
illustration of this problem is the fact that, in the analysis above, functional pressures for
delegation were taken into account only through a time-invariant dummy for economic
and social regulation. Some improvement could be achieved, but not much. In other
words, most of the hypotheses presented in section 3 cannot be tested, and notably those
In the second step of the analysis, then, I move to event history analysis. The unit of
analysis is no longer the sub-population/year, but the single regulatory domain in a
single country. Concretely, the information contained in the dependent variable tells
when a single IRA was set up in a given regulatory domain of a given country: for
example, when an IRA for telecom was established in the UK. This shift to the micro
level solves both problems. First, the impact of the number of existing IRAs is now
studied on individual IRA creations and not on the evolution of the population. If it is
found to be significant, it will be much more difficult to argue that it is a mere statistical
phenomenon common to all sorts of diffusions. Second, the limits in the capacity to
control for variables are due only to data limitations and not to limitations built into the
model. The results of the event history analysis will be a much stronger test of the
relevance of symbolic diffusion in explaining the observed pattern of IRA creations.
Individual IRA creations can be analysed through event history analysis models.
Event history analysis is a statistical technique explicitly devised to study the pattern
and determinants of the occurrence of events (Allison 1984; Yamaguchi 1991). The
establishment of an IRA is the relevant event in the context of this study. I employ here
the widely-used Weibull model, which takes the form (Box-Steffensmeier and Jones
h(t) = h α(ht)α-1
and which is estimated through the equation
h(t) = exp(βX + αlnt)
where h(t) is the hazard rate, βX is a vector of the independent variables and their
coefficients, and α is the shape parameter, whose estimate indicates the effect of time.
The hazard rate is a key concept in event history analysis. It is defined as "the rate at
which a duration or episode ends in the interval [t, t + ∆t], given that the duration has
not terminated prior to the beginning of this interval." (Box-Steffensmeier and Jones
h(t) = lim∆t→0 P(t + ∆t > T ≥ t | T ≥ t) / ∆t.
If the baseline rate α and the explanatory variables are taken into account, the hazard
h(t) = lim∆t→0 P(t + ∆t > T ≥ t | T ≥ t; α; βX) / ∆t.
From these two equations it appears that the hazard rate is basically a probability
(though it can be bigger than one), and precisely the instantaneous probability that the
event occurs in the interval [t, t + ∆t].
The results of the analysis are presented in Table 2. The difference between the three
models lies in the level at which the number of IRAs existing at time t-1 (the proxy used
for symbolic diffusion) is computed. In the first model (whose results will be examined
in detail), the number of IRAs refers to IRAs in economic or social regulation; in the
second, to the overall number of IRAs; and in the third, to the number of IRAs in the
same regulatory domain. It can be seen that estimates do not change much between the
first and the second model: signs do not change at all and significance levels change
only slightly. In the third, on the other hand, the impact of the number of IRAs is
What do these results tell about diffusion of IRAs? The first model shows that the
number of IRAs of the same type (i.e. economic or social regulation) has a positive and
significant impact on the hazard of IRA creation. This evidence supports the hypothesis
that symbolic imitation has been at work (hypothesis 6). On the other hand, the
interaction between the number of IRAs and liberalisation (i.e. a functional pressure for
delegation) (hypothesis 7) is unexpectedly negative, but significant only at the 10% level.
Additional analysis (not shown) also indicates that here is no interaction between
privatisation and the number of IRAs, nor between it and competition / financial
markets. This is not consistent the symbolic imitation hypothesis, which is however
supported by the significant independent effect of the number of IRAs. Further, EU
directive 97/51 (amending dir. 90/387 and 92/44 for the purpose of adaptation to a
competitive environment in telecommunications) has a strongly significant positive
impact on the hazard of IRA creation, thus suggesting the existence of coercive
isomorphism (hypothesis 8). On the other hand, additional analysis (not presented here)
shows that EU directive 96/92 (common rules for the internal market in electricity) has
no such effect. It must be said that, although both the telecom and electricity directives
leave considerable manoeuvring room to member states with respect to the set-up of
IRAs, the electricity directive is less explicit on this point.
There is also abundant evidence that the spread of IRAs has been partially driven by
spurious diffusion. First, both privatisation and liberalisation have a significant positive
impact on the likelihood that an IRA is created, thus supporting hypothesis 1. The set-
up of IRAs is also more likely in competition and financial markets than in other
regulatory domains (controlling for liberalisation and privatisation in electricity and
telecoms), which is consistent with the prediction of hypothesis 2. These two findings
confirm that one of the reasons of the creation of IRAs is the need to improve the
credibility of policy commitments. A second spurious diffusion mechanism is related to
political uncertainty. The risk for a government of being replaced by a coalition with
different preferences increases the hazard of IRA creation (hypothesis 3). Further, its
impact depends on the average level of replacement risk in a given country, as predicted
in hypothesis 4. On the other hand, the role of veto players / political constraints
(hypothesis 5) is only partially confirmed. A significant mediating effect is found only
for competition and financial markets, and to some extent for replacement risk
(significant at the 10% level), but not for liberalisation and privatisation (as indicated by
additional analysis not shown here).
Finally, the model includes three variables that were originally intended to be for
control only, but which turned out to supply interesting insights. In effect, the partisan
composition of governments seems to be a relevant explanatory variable, in particular in
mediating the effects of liberalisation. The sensitivity of governments to symbolic
imitation also seems to depend on their partisan composition. Although I had no
specific hypotheses on these effects, the results are interesting and add to our
understanding of the diffusion of IRAs.
Looking at coefficients is useful, but their direct interpretation is not always
straightforward. Thus, I have drawn figures of predicted hazards of IRA creation for
some of the most interesting results.
Figure 5 shows symbolic and spurious (liberalisation / privatisation) diffusion effects
in the choice to set-up IRAs. It appears clearly that both types of diffusion are present.
Both liberalisation and privatisation increase the hazard of IRA creation, but the impact
of the latter is much stronger, as indicated by the vertical distance between the curves.
There are also strong symbolic imitation effects. The likelihood that an IRA is created
increases tremendously when the number of existing IRAs goes up. This is a clear
manifestation of symbolic diffusion. Governments are influenced by concerns that are
not related to problem-solving when deciding to set-up IRAs. However, it is not
possible to discriminate legitimacy-seeking from taken-for-grantedness.
Figure 6 shows that the impact of symbolic diffusion varies with the partisan
composition of governments. Centre-right governments are more sensitive to the taken-
for-grantedness or legitimacy-enhancing effects of IRAs than are centre-left
governments. After a certain threshold (around 30 IRAs), the creation of an IRA even
becomes more likely under a centre-right government without privatisation than under a
centre-left government with privatisation. The question remains of why are centre-right
governments more sensitive to symbolic diffusion than centre-left governments. A
possible answer could be that the values that are diffused are more in line with the
preferences of centre-right governments than is the case with centre-left governments. If
this is true, a similar effect could be found also for central banks.
Figure 7 further examines the effects of spurious diffusion, and notably privatisation
/ liberalisation and the partisan composition of governments on the set-up of IRAs.
Under centre-right governments the hazard of IRA creation is always higher than under
centre left-governments, but interaction effects exist only for liberalisation. Privatisation
increases the likelihood of IRA creation for both centre-right and centre-left
governments. Liberalisation, on the other hand, increases the likelihood for centre-right
governments, but decreases it for centre-left governments. This is an indication that when
centre-left governments liberalise telecoms or electricity (for reasons that are beyond the
scope of this paper, see e.g. Levi-Faur 2002), they want to keep a more direct control
over these sectors than does the centre-right. They are more afraid of the possible
negative effects of the free market, and are less willing to reduce their intervention
possibilities. When it comes to privatisation, on the other hand, both centre-right and
centre-left governments acknowledge that delegation is necessary for a credible
commitment vis-à-vis those who buy shares of the privatised company, who appreciate
guarantees against expropriation dangers (Spiller 1993). In addition, short of
liberalisation most of the fears associated to the free market do not emerge, which
explains the willingness of centre-left governments to give up some of their direct
Figure 8 examines the last source of spurious diffusion, namely political uncertainty,
and more precisely the risk for a government of being replaced by a coalition with
different preferences. It can be seen that the impact of replacement risk depends on how
uncommon is a situation of high replacement risk in a given country. Generally,
replacement risk has a positive impact, as predicted by hypothesis 3 and 4, except in
countries where average replacement risk is high (i.e. above the mean of all countries,
which covers 1/3 of the sample). In these countries replacement risk has a negative
impact. This is surprising because, though hypothesis 5 predicts that in these countries
the impact of replacement risk is not the same as in countries with low average
replacement risk, it does not predict that it is negative. These findings seem partially
consistent with recent results on the strategic manipulation of public debt, which, not
unlike IRAs, can be a means to constrain the choices of the opposition when it will gain
power. Franzese (2002) finds that incumbents who expect frequent oscillation in
government may be unwilling to bind themselves to constrain their opposition because
they expect to hold office again soon, while with less frequent oscillations the larger
expected time between offices leads them to consider strategic manipulations of budget
deficits. The findings also seem consistent with de Figueiredo's (2002, 2003) results,
which suggest that governments are not willing to pay the cost of insulating their
policies if, when they face replacement risk, they expect to be back in power soon. What
remains puzzling is that, when expecting frequent oscillations, governments are not
insensitive to replacement risk but, rather, are more willing to impose constraints to
their opponents when current replacement risk is low.
The results of the analysis can be summarised quite briefly: interdependent diffusion,
in the form of symbolic diffusion, has driven the spread of IRAs in Western Europe, but
only in part: spurious diffusion, in the form of credible commitment and political
uncertainty, has played an important role too.
This paper sought to conceptualise and explain the spread of IRAs in Western
Europe. It started from the observation that the empirical pattern of the creation of IRAs
has an S-shape that is one of the main constants of diffusion studies. This suggests that
the spread of IRAs may have been driven by a diffusion process, i.e. a process where the
main actors, namely governments, act interdependently rather than independently.
The conceptualisation of the diffusion of IRAs put forward here (see figure 3) firstly
distinguishes between spurious and interdependent diffusion. Spurious diffusion occurs
when actors respond in a similar way to similar functional pressures at roughly the
same time, like people opening umbrella when it starts raining. In the case of IRAs, such
pressures are best identified with liberalisation, privatisation, and more generally
economic regulation, which are domains where the need to achieve credible
commitment capacity gives governments incentives to delegate some of their regulatory
powers. A second element that may give such incentives is political uncertainty, and
more precisely the risk for a government of being replaced by a coalition with different
preferences. In this case, IRAs are a means to constrain the policy choices of future
Spurious diffusion is to be distinguished from interdependent diffusion because
actors do not behave in response to each other actions. It still deserves to be called
diffusion, albeit with a strong qualification, because it may lead to an outcome which is
very similar to that of interdependent diffusion. In the latter, actors are interdependent
and do behave in response to each other's actions. Interdependent diffusion mechanisms
can be distinguished with respect to how they are related to problem-solving.
Sometimes actors look at each other to improve their problem-solving capacity. In this
case, we found mechanisms such as learning (rational / bayesian or bounded) and
regulatory interdependence (cooperative and competitive). On the other hand, if actors
are influenced by the behaviour of other actors independently from the problem-solving
benefits they can get, diffusion can be conceptualised as isomorphism and as symbolic
imitation. In the latter, mechanisms such as taken-for-grantedness and legitimacy-
The analysis was limited to an examination of the relative importance of spurious and
symbolic diffusion in the spread of IRAs. An implication of the latter is that the number
of agencies existing at time t-1 should, ceteris paribus, have an impact on the choice to
set-up an IRA at time t. This hypothesis has found empirical support, thus corroborating
the claim that there has indeed been symbolic diffusion of IRAs. On the other hand, the
analysis has also clearly shown that spurious diffusion has also been at work: the need
to improve credible commitment capacity and political uncertainty increase the
In conclusion, it should not be overlooked that other diffusion mechanisms have not
been included in the empirical analysis. Learning in particular, both rational /bayesian
and bounded, has a prima facie high relevance, and future research should try to deal
with it. The empirical difficulties of such a task make the enterprise all the more
number of IRAs created in each year and author's data set
1 = economic regulation (electricity,telecom, financial markets, competition),0 = social regulation (food safety,pharmaceuticals, environment)
years since the creation of the first IRA
years since the creation of the first IRA
in the PoliticalContraints Data Set(Henisz 2000)
Parliament and of the Council of 6October 1997 amending CouncilDirectives 90/387/EEC and 92/44/EECfor the purpose of adaptation to acompetitive environment intelecommunications.
Nicoletti (2000), Levi-Faur (2002), OECDregulatory database
average of replacement risk over allavailable years (roughly 1953-1999)
situation, 4 = left-centre complexion, 5 =
Appendix 2. Operationalisation of political uncertainty
Following Franzese (2002), replacement risk is operationalised as the product of hazard
rate and a standard deviation of the partisan "centre of gravity" of governments across
The hazard rate is operationalised as the inverse of actual duration of governments.
Raw data on the actual duration of governments are taken from Woldendorp et al.
(2000), who give the duration in days of each government from about 1945 to 1998. Data
for more recent governments are taken from various special issues "Political Data
Yearbook" of the European Journal of Political Research", as well as from several online
sources, mainly BBC's "country profiles"
(http://news.bbc.co.uk/2/shared/bsp/hi/country_profiles/html/default.stm) and
The Economist's "country briefings" (http://www.economist.com/countries/).
The units of the raw data are governments. For example, Woldendorp et al. (2000)
report that Germany's 22nd post-war government began on 30 March 1983 and lasted
1442 days. The relevant units for my purposes are years, so the data must be
transformed. I have first translated duration from days into years by dividing it by 365,
and then calculated its inverse (1 / duration in years). The problems remains of how to
deal with years where there is a change of government. I follow Franzese (2002) and
take mean of the duration of the governments that were in place, weighted by the share
of the year that each holded office. For example, in France there was a change of
government on the 28th of June 1988. The hazard rate for 1988, then, is 50% that of the
first government, and 50% that of the second. For attributing weights, I have considered
only months, and not days. Months are attributed to a given government if it was in
office for at least 15 days of that month.
The centre of gravity of governments is measured following Woldendorp et al. (2000),
who, in their data set, have an indicator called "ideological complexion of government
and parliament" which accounts for the relative strength of parties in government with
reference to the left-right dimension, through a five-point scale in which the
proportional shares of left, centre and right parties are coded 1 to 5. Scores represent the
degree of dominance of either party both in parliament and government (1 is right wing
and 5 is left-wing dominance). This is admittedly a rough measure, but, for my
purposes, I prefer it to alternative, more refined measures such as that of Budge et al.
(2001). These authors have developed measures based on party manifestos and collected
an impressive data set where detailed information on the policy preferences of parties
over fifty years. Using these data to measure the centre of gravity of government,
however, is problematic since the policy position of parties may change over time, often
does change and sometimes changes dramatically. For my purposes, this can lead to the
paradoxical result that replacement risk increases (through centre of gravity) even
though there has been no party change in government. For this reason, I have used the
Woldendorp et al. (2000) measure and data. Their data are until 1998 at best; I have
updated them from various sources, mainly the same I used for the hazard rate (see
Secondly, there is the problem of what standard deviation of the centre of gravity is
more appropriate. Franzese uses a moving nine years standard deviation centred on
present. This implies that governments base their estimates on the experience of the
previous four years as well as on a perfect foresight four years ahead. The idea is that
governments are not fully backward-looking, but have some guesses with respect as
how their re-election prospects will evolve in the near future. I keep this assumption,
but use a seven-year standard deviation with five years back and one forward. The main
reason for this choice is that the most recent year are among the most important, and
certainly more important than the 1950s. Including many years forward would have
prevented me to take most of the 1990s into account. On the other hand, I wanted to
keep the assumption that governments have guesses about their fate in the near future.
Assuming that they can see one year ahead seems reasonable.
7 I would like to thank Robert Franzese, who kindly answered some questions I had on hisoperationalisation of replacement risk.
Figure 3. Eight mechanisms of policy diffusion
Figure 4. Impact of the total number of IRAs on new
Figure 5. Symbolic and spurious diffusion of
privatis. onlyboth liberalis. and privatis.
Number of IRAs (economic or social regulation)
Figure 6. Symbolic and spurious diffusion of
Number of IRAs (economic or social regulation)
(liberalisation / privatisation) (Weibull
low average repl. risk (Swi, Ger, Aut)
high average repl. risk (Ita, Gre, Fra)
Table 1. Spurious and symbolic diffusion of IRAs: Poisson modelNote: * p<0.10, ** p<0.05, *** p<0.01; standard errors in parentheses. Maximum likelihoodestimation.
Table 2. Spurious and symbolic diffusion of IRAs: Weibull model
(compet. / fin. markets) x (pol. constr.)
Note: Maximum likelihood estimation (streg command in Stata). Robust standard errors in parentheses. * z < 0.1, ** z < 0.05, *** z < 0.01.
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