Path: > Syllabus > Topics and Readings >
Lane & Ersson

Dimensions of Party Systems

Lane & Ersson Reading

Chapter 5

Party Systems

From Jan-Erik Lane and Svante Ersson, Politics and Society in Western Europe (London: Sage Publications, 1987), pp. 154-179.

West European Political parties are analysed at length in Chapters 3 and 4. The focus is on the single parties, their continuity and social bases, but political parties constitute party systems and require their own analysis. Let us focus now on systems of political parties by looking at the West European party system from the perspective of stability. The well-known stability hypothesis in comparative research claims that the West European party systems are characterized by a high degree of continuity. Thus, it has been argued that change is not a typical feature of the party systems of Western Europe. Seymour Martin Lipset and Stein Rokkan state in their analysis of the development of party systems since these political systems were transformed into democracies:

the party systems of the 1960s reflect, with few but significant exceptions, the cleavage structures of the 1920s. This is a crucial characteristic of Western competitive politics in the age of 'high mass consumption': the party alternatives, and in remarkably many cases the party organizations, are older than the majorities of the national electorates [Lipset & Rokkan, 1967a:50).

Richard Rose and Derek Urwin came to the same conclusion with a refined analysis of the development after the Second World War:

 Whatever index of change is used--a measure of trends or any of several measures of fluctuations--the picture is the same: the electoral strength of most parties in Western nations since the war had changed very little from election to election, from decade to decade, or within the lifespan of a generation. The consistency of this finding increases confidences in the indicators used. In short, the first priority of social scientists concerned with the development of parties and party systems since 1945 is to explain the absence of change in a far from static period in political history [Rose & Urwin, 1970:295].

 This widely accepted interpretation of the party systems in Western Europe may be challenged by means of a new analysis of the data. Although we focus in this book on the post-Second World War period we include the between war years to test the Lipset-Rokkan stability hypothesis as it relates to party systems. When one sets out to inquire into how much party system change has taken place in West European party systems since the democratization of the political systems the notion of party-system change becomes crucial. The concept of party system change consists of two components: party system and change or instability which both require theoretical clarification.

A party system like any system consists of parts and relationships between these parts: 'A system is a set of objects together with relationships between the objects and between their attributes' (Hall & Fagen, 1956:18). The parts of a party system are, of course, the political parties, but the specification of relationships is not as simple as the specification of the parts (Daalder & Mair, 1983). Lipset and Rokkan as well as Rose and Urwin approach the problem of party-system change as a matter concerning the development of the parts of the party systems. We suggest that the concept of party-system change must be tied to that of party-system dimensions, which cover the parts of the system studied and the relationships between them. It is a matter of research strategy which parts and which relationships are to be singled out as crucial in the analysis of party-system change. It seems appropriate to base any judgement of the occurrence of change

and no change on an investigation of those dimensions of party systems in Western Europe that- according to a factor analysis--explain most of the variation.

The concept of change or stability in relation to party systems stands for properties of the development over time in the party-system dimensions. The development since 1920 of these party-system dimensions may be described by means of regression equations in a time series analysis of the various national party systems. Important distinctions between developmental properties may be introduced and operationalized in relation to the estimated values of these regression equations. Following Rose and Urwin, we argue that it is illuminating to distinguish between two different types of party-system change or instability: trend and fluctuation (Rose & Urwin, 1970:29 1). 

Dimensions of Party Systems

 It is generally agreed that a party system is an entity that is different from a political party or a simple set of political parties, as a party system involves organization. A party system consists of a set of political parties operating within a nation in an organized pattern, described by a number of party-system properties. This is where the agreement ends, as scholars do not identify the same set of properties.

There are a number of relevant party-system properties and little justification for the use of one or two of these to the exclusion of the others. The study of party systems faces a conceptual problem about what the semantically relevant properties of party systems are. A semantically relevant property is a property that typically occurs in a set of phenomena and that characterizes part of the similarities and differences between phenomena in that set, which makes it useful for definition purposes (Achinstein, 1968).

Various definitions, stating the necessary and sufficient conditions for the application of the term party system have been suggested. The proposals for a definition of the concept of party system include:

In the second place a comparison between the various parties makes it possible to distinguish new elements in the analysis that do not exist for each party community considered in isolation: numbers, respective sizes, alliances, geographical localization, political distribution, and so on. A party system is defined by a particular relationship amongst all these characteristics [Duverger, 1954:203).

 The subject of 'party systems' is concerned with the interaction patterns among significant and genuine electoral organizations in representative governments--governments in which such systems serve pre-eminently (whether well or badly) the functions of providing a basis for effective authority and for defining choices that can be resolved by electoral processes [Eckstein, 1968:438].

 The network of competitive relationships between political parties is what I mean by the term political party system. The party system is not literally a collection of parties--men, institutions, activities. It is instead the competition between these parties within a single political regime, and it is this system of competition (the party system) which gives to democratic political parties their unique importance [Rae, 1971:47].

 Parties make for a 'system', then, only when they are parts (in the plural); and a party system is precisely the system of interactions resulting from inter-party competition. That is, the system in question bears on the relatedness of parties to each other, on how each party is a function (in the mathematical sense) of the other parties and reacts, competitively or otherwise, to the other parties [Sartori, 1976:441.

The definitions fall into two sets; the proposals of Eckstein, Rae, and Sartori are general since they state that a party system is more than the sum of its parts; on the other hand, the suggestion by Duverger may result in an infinite enumeration of properties. We need a set of minimal properties by which to characterize a maximum amount of actual party-system variation. Perhaps at the present stage of knowledge concerning political parties the search for a definition stating the necessary and sufficient properties is premature. The best strategy is to try to derive a tentative list of semantically relevant properties, even though such a list would need revision before a definition is arrived at.

Most typologies of party system identify one or two dimensions along which various party systems are classified. Number of parts in a party system is a property that is almost always considered a basic dimension; Duverger is famous for his classification scheme of the single-party, the Anglo-Saxon two-party, and the multi-party system (Duverger, 1954:203). In the same vein Blondel talks of two-part systems, two-and-a-half-party systems and multi-party systems with or without dominant parties (Blondel, 1968:187). Sartori's mode includes besides party fragmentation (number of parties) ideological distance (Sartori, 1976:282-93). Mogens Pedersen states that polarization and fragmentation have, of tradition, been identified a the party system dimensions and adds a typology based on volatility to the growing literature on party systems (Pedersen, 1979:3). The Lipset and Rokkan model focusses upon the cleavage lines that distinguish the various parties in a party system from each other (Lipset and Rokkan, 1967a:33 50). Thus, typologies of party system identify either relationships between the constituent parts of the system or properties of the parts of the system. However, the basic conceptual problem is still unresolved: How many dimensions are to be included in a party-system model (Gross & Sigelman, 1984)?

A number of indicators are used to characterize party systems. What is the proper procedure for identifying the party-system dimensions employed to describe party systems? We argue that those properties that explain most of the variation in a set of party system constitute the dimensions. The derivation of the concept of party system thus depends on which party systems are studied--at the present state of knowledge. As knowledge grows it might be possible to identify by definition a set of properties appropriate for the analysis of all kinds of party system. We confine ourselves to the identification of the properties that explain much of the variation among the party systems we study, viz., the West European ones. Thus, the dimensions we focus upon are the semantically relevant properties of the concept of party systems as it relates to Western Europe.

Using factor analysis of the indicators on a number of party-system properties we derive those dimensions that explain the variation among West European party systems. What are the basic dimensions when relevant party-system properties are operationalized by means of indicators measuring party-system variation in Western Europe? It should be emphasized that the factor analysis considers only system properties, since the focus of analysis is the party system not the political party. Moreover, the selection of party-system indicators has been made considering existing typologies; thus, we arrive at the following sets of indicators corresponding to the one- or two-dimensional models previously referred to: number of parties, ideological distance between parties, realignments behind the parties, and cleavage lines in the party system.


 A number of indicators are connected with the number of parties and the strength of parties. The indicators we considered in this connection are:

1. Number of parties; i.e., the number of parties that have taken part in parliamentary elections and become represented in parliament, irrespective of how small they are--also certain non-represented parties like the minor communist parties have been taken into account; operational definition: parties included in Mackie and Rose: International Almanac of Electoral History (1982).

 2. Number of relevant parties; Sartori (1976:122-3) lays down certain rules for what parties are to be counted as relevant within a party system: on the one hand the parties must show continuity over time, on the other hand they should have a coalitional potential (applies to small parties in the political centre) or a blackmail potential (applies to large extremist parties).

 3. The fractionalization index is where:

F = 1-pi2 [pi = the proportion of seats held by party i] [4]

 Rae is the one to whom the credit for this index is due which measures both the number of parties and their size. Much has been written about this index' but we agree with Pedersen who writes: 'It might be a good idea, therefore, if students of systems would decide to stick to one measure--namely, F [i.e., Rae's]. Instead of inventing new indices of fragmentation, one could instead concentrate on the task of delimiting the contexts in which F can legitimately be used' (Pedersen, 1980:397; see also Laakso and Taagepera, 1979).

 4.The aggregation index is where:

the share of the largest party;
the number of parties. [5]

 An index with this designation was constructed by Mayer (1980:517) and it measures the share of the largest party in relation to the number of parties (we have modified Mayer's original formula).

A set of indicators expresses the ideological distance within a party system; as a rule the distance on a right-left scale is referred to. Even if one-dimensional measures like the right-left scale are criticized, they catch an essential dimension within the party systems. The starting point is to classify parties on a right-left scale, a problem attended with great difficulties. We have used a scale of seven degrees: the extreme right is given the value--3, the political centre is given the value 0, and the extreme left the value + 3. As indicators we use:

5. Right-left score: this value shows the point on the right-left scale a party system reaches at a certain election, and this value is weighted on the basis of the electoral strength of the parties.

6. Polarization index: here we use the same index as Taylor and Herman (1971) and Sigelman and Yough (1978); a system is polarized maximally when 50 percent of the electorate is at the respective pole, whereas there is no polarization if all are in the political centre. Our formula for the polarization index is:

P = nfi (xi- X)2 [6]

 where n isthe number of parties, fi is the share of vote of the respective party, xi is the right-left score of the respective party and X is the right-left score the party system.

 7. The share of communist parties as well as the share of communist parties, fascist parties, and discontent parties; Sartori (1976:132-4; 317-8) regards the size of anti-system parties as a measure of ideological distance; we use the two indicators as measures of the

 [8.] size of anti-system parties.

These measures may be compared with other measures stated in the literature. We tested our classification of parties on a right-left scale against the one employed by Janda, 1980 (BV 514/15): r = .92 (N = 3 5) in relation to a scale employed by Castles and Mair (1984) we have a correlation with our measure of: r = -.92 (N= 79); we find a similar correlation when comparing with De Swaan's classification from 1973: r = -.90 (N=60). De Swaan makes some pertinent comments on difficulties of classifying parties in this way (De Swaan, 1973:132-43). Moreover we have tested the distance between different couples of parties on the right-left scale, as it has been estimated on the basis survey data described in Inglehart and Klingemann (1976:255) and in Sani and Sartori, (1983:322-23); the correlation between our values an their values is r = .77 (N= 9) and r = .95 (N= 21) respectively; the correlation with the distances reported in Castles and Mair (1984) i r = .86 (N= 113). Concerning the values for the right-left score of the party systems we tested our values against the values stated by Sigelma and Yough (1978:377); r = .91 (N= 12). We have also tested our value for the polarization index against other values stated in literature; the testing gives the following connections: compared to Sigelman an Yough (1978:377), r = .87 (N = 12), compared to Sani and Sartori (1980:11), r = .74 (N= 10) for the respective period, i.e., the 1960s an the 1970s.

There are indicators that somehow reveal the dynamics of party systems, i.e., they express changes within a party system. We take two indicators into account:

9. Volatility: the formula for volatility is given by Pedersen (1979:4) as
Vi, = 1/2 * n | pi ,t | [7]

where n is the number of parties participating in elections at the time t and/or t-1, and delta pi stands for the change in the share of the vote of the party over the two elections. This measure shows net changes for all the parties within a party system between two elections; gross changes are possible to estimate estimate only on the basis of survey data. Pedersen (1979:4) names the concept volatility, but it has been used by other scholars under other designations (Przeworski, 1975:53; Dodd, 1976:88).

10. Party changes; this is a measure analogous to volatility, but it refers to changes in the number of parties within a party system from one election to another (here we have avoided dividing the absolute value by two).

A large number of indicators may be devised that measure the occurrence of social cleavages in the party system. This was the focus of the famous Lipset and Rokkan analysis in their introduction to Party Systems and Voter Alignments (1967). According to them, the modern party systems of Western Europe are the result of a process through which various cleavages in society are transformed into the various voter alignments of the party systems.

The idea of some kind of relationship or correspondence between party system and social cleavages recurs among several scholars. Bingham Powell refers to the 'relationship between party systems and societal cleavage structures' (Powell, 1980:13), and Hans Daalder states that 'European countries reveal considerable differences according to the character and the intensity of the cleavage lines that form the basis for political conflict and political organization' (Daalder, 1966a:67).

We use the following indicators to cover as much as possible the idea of the social orientation of party systems. All these indicators are based on a classification of nearly all political parties in ten party types, see Chapter 3. Thus, we have:

 11. Ethnic and religious score, i.e., the shares of ethnic and religious parties.

 12. Conservative and liberal score, i.e., the shares of conservative, liberal and agrarian parties.

 13. Working-class score, i.e., the shares of communist, socialist and left socialist parties.

 14. Bourgeoisie score, i.e., the shares of conservative, liberal and agrarian parties.

Factor Analysis

 A factor analysis has been made comprising the preceding indicators for the purpose of deriving the basic dimensions of the party systems of Western Europe. A priori it is difficult to hypothesize about how many factors the analysis will arrive at and which factors will be interpretable theoretically. Since the dominant mode of analysis concerning party systems is the one- or two dimensional model, it would be an interesting finding simply to arrive at more than two interpretable factors (Table 5:1).

TABLE 5.1 Factor Analysis of Party System Indicators (Varimax Rotation)
Factor 1
Factor 2
Factor 3
Factor 4
Factor 5

Number of parties


Number of relevant parties


Fractionalization index


Aggregation index


Right-Left score


Polarization index


Communist-party share


Anti-system score




Party change


Ethnic and religious score


Conservative and liberal score


Bourgeoisie score


Working-class score


Percent explained variation

Note: The factor analysis is based on data covering all national elections in sixteen European democracies roughly between 1920 and 1984 (N = 272).

Source: The indicators we give an account of are based on data from 272 elections in sixteen West European party systems at the most for the period 1920-84. Our most important source has-been Mackie and Rose. The International Almanac of Electoral History (1982) and its yearly updatings in European Journal of Political Research. We have also used Rokkan and Meyriat, International Guide to Electoral Statistics (1969: Greece: 1926-64, Italy: 1919-21. France: 1919-36. For the election results in France after 1960, checks have also been made against Borella (1977), Steed (1979), various issues of Cahiers du communisme (Elections legislatives). As far as possible, occurring joint-lists have been broken down on the respective parent party; the estimates made in this connection are based on comparisons of the shares of the parties at the regional level. This procedure has been followed for Belgium, Norway and Sweden.

We arrive at five factors and these factors may be interpreted as the dimensions of Western European party systems.

1. The first factor is the amount of fractionalization of party systems; both the Rae fractionalization index and number of parties 'load' significantly on this factor.

2. Factor 2 deals with the extent of the functional orientation of the party system: the higher the ethnic and religious score the less the functional orientation of the party system, the higher the score for conservative liberal and agrarian parties the more functionally orientated is the party system.

3. The polarization of a party system comes out as the third factor. Both the polarization index and the communist-party share load on this factor.

4. Factor 4 consists of the extent of the radical orientation of a party system as measured on the one hand by the working-class score and on the other hand the right-left score.

 5. The last, and fifth factor, is the volatility of a party system.

A typical theme in the study of party systems is the use of one- or two-dimensional models. The factor analysis indicates that any such model would be inappropriate for the study of party-system variation Western Europe. There is no factor that has a significantly high eigenvalue (explained variation) than the other factors. Moreover, the ranking order of the factors is not stable as we move from orthogonal solution to an oblique solution, although the factors are the same. Thus, there are no one- or two-party system dimensions that may be singled out as more important than any other.

West European party systems may be approached as consisting of five separate dimensions: fractionalization, functional orientation, polarization, radical orientation and volatility. These five dimensions cover somewhat more than 85 percent of the variation in the data and all dimensions have an eigenvalue greater than one. We regard functional orientation, fractionalization, radical orientation, polarization, and volatility as the semantically relevant properties of the concept of a party system; these properties may be employed to test the hypothesis that the West European party systems are characterized by stability or continuity. They may be described either by means of factor scores or by the selection of one indicator for each dimension among those indicators that show high factor loadings. Although it creates some problems, we choose the second method because it is not the case that one single indicator taps all the variation in the factor at stake. The selection of the indicators on these five dimensions include:



fractionalization index

functional orientation


bourgeois score



polarization index

radical orientation


working-class score



volatility index

Now let us proceed to inquire into the development of West European party systems over time to pinpoint seminal trends.

Development of West European Party Systems

The longitudinal analysis of aggregated cross-sectional data is based on Table 5:2. It covers twelve five-year periods, and two different methods of calculating the variation in party-system dimensions are employed.

TABLE 5.2 General Development of the Set of West European Party Systems
1920-1984 (Mean Values)

Functional orientation
Radical orientation
Time period

Notes: (1) = Values based on all elections (N= 272)

(2) = Values based on mean values for all party systems (N =11 - 6)

Fractionalization: A typical feature of West European party systems before and after the Second World War is the variety of political parties. The fractionalization index displays high values for all intervals of time since 1920. The extent of fractionalization was highest in the early 1920s, decreasing during the 1930s and reaching its lowest values in the 1950s. Since 1960 the amount of fractionalization has been increasing, though there are signs indicating that it culminated in the early 1970s.

Functional Orientation: It used to be the case that European party systems as a whole were characterized to a significant extent by a functional orientation, as the aggregated share of the votes for the conservative, liberal and agrarian parties amounted to almost 50 percent of the total vote. Since the Second World War, however, there has been a downward trend as the &hare of the ethnic and religious parties has increased at the expense of the traditional bourgeois parties.

Polarization: Polarization, or the distribution of the electorate along the classical right-left scale, is a clear property of European party systems during ill the time periods. However, the amount of polarization cannot be described as exceptionally high, because theoretically it is conceivable hat party systems reach as high a degree of polarization as 9.0. Generally speaking, an increase seems to have occurred in polarization since the 1960s. Of course, we find a high degree of polarization during the 1930s.

Radical Orientation: For the set of European party systems, generally, a steady and continuous growth in left-wing parties has taken place. When the European political systems were democratized in the early decades of the century, the left-wing parties secured hardly one third of the total vote; it seems as if the Second World War had a significant impact on the attractiveness of left-wing parties since during the post-war time intervals they receive roughly 40 percent of the total vote.

Volatility: The maximum and minimum values of volatility are theoretically 100 and 0, respectively. During all the intervals of time we observe the occurrence of net changes in voter support for political parties, but European party systems can hardly be characterized as extremely volatile, as the index ranges from roughly 6 to roughly 18. However, there is an interesting variation over time. The Second World War broke normal ways of party functioning, which had the result that the electorate immediately after the war faced some difficult choices as to how to realign itself towards old and new parties. Consequently the period 1945-49 has the highest degree of volatility. The 1950s give the impression of firm voter alignments, whereas we observe a clear increase in volatility between 1965 and 1974. The data indicate that the level of volatility is still high in the early 1980s.

The data presented hitherto neglect what to some scholars is most interesting concerning the party systems of Western Europe: the variation between nations. We turn now to the analysis of the ways in which national party systems vary in the five dimensions derived (Table 5:3).

[Table 5.3 has been omitted]

Variation Between Nations Pre-1945 and Post-1945

Fractionalization: The degree of fractionalization does not vary much, because the European party systems are typical multi-party systems. There is a set of national party systems that are very much fractionalized comprising Finland, the Netherlands, and Switzerland as well as France and Germany before the Second World War. Inversely, the set of nations that score low--relatively speaking--consists of Austria, the United Kingdom, Ireland, and the Federal Republic of Germany after the Second World War.

Functional Orientation: The functional orientation index captures a variation between two kinds of alignment: either the voters support traditional bourgeois parties--conservative, liberal or agrarian parties--or they support non-functionally oriented parties--ethnic or religious parties. The index reveals significant variations in the way the non-leftist vote is distributed between these two blocs. In some nations the traditional bourgeois parties are strong: Greece, France, the UK, and the Nordic countries. Some national party systems are dominated by the existence of ethnic or religious parties: Austria, Belgium, Italy, the Federal Republic of Germany, and the Netherlands.

Polarization: The variation in polarization is striking as a few nations are twice as polarized as some others. Polarization is a typical feature of France,F inland, the UK as well as Germany before the war. On the other hand, polarization assumes no great importance in Ireland, Switzerland, the Netherlands, and Belgium. The index is however heavily influenced by the strength of extremist parties. If, e.g., the Austrian Social Democratic Party is classified as a semi-communist party during the First Republic, then the score for Austria would have been much higher.

Radical Orientation: A party system may be characterized by the numerical strength of left-wing parties. Actually, the extent of variation in the electorate concerning the orientation towards socialist and communist parties including left-socialist parties) is great. Radical orientation has not been a typical feature of Greece (except in the 1980s), Ireland, and Switzerland, whereas the contrary is true of the Nordic countries as well as Austria, France (after 1945), Italy (after 1945), and the UK (after 1945).

Volatility: It is necessary to make a distinction between volatility before and after the Second World War, because the inter-nation variation is not the same. Volatility pre-1945 is an aspect that distinguishes Greece, France, Germany, Ireland, and the United Kingdom. We find a low degree of volatility among nations such as Denmark, Switzerland, Belgium, Finland, and the Netherlands. After 1945, volatility was high in: Greece, the Federal Republic of Germany, France, Denmark, and Italy; the set of nations with a low degree of volatility includes Austria, Sweden, Switzerland, and the United Kingdom.

Party-system Change

The fundamental problem in the study of West European party systems pertains to the extent to which the party systems are characterized by change or stability. It is argued that the national party systems are moving towards a higher degree of instability (Pedersen, 1979:24; Borre, 1980:162-3; Maguire, 1983; Shamir, 1984). We present data on the extent of party-system change and instability in European democracies for two periods covering 1920 to 1984. Before we interpret these data we deal with what party-system change and party-system stability are, and how party system change or stability is to be measured. A solution to these problems is a necessary step towards an empirical analysis. Actually, the concept of party-system change or stability presents intricate problems of both a conceptual and an operational nature.

There are no standard definitions of the concepts of party-system change and party-system stability; it may even be argued that these terms are ambiguous. Moreover, in the literature on party systems it is not clear how the concepts of party-system change and party-system stability are interrelated or how they are to be operationalized. Our suggestion is that these concepts should be clarified by substituting the more precise concepts of trend and fluctuation, concepts which may be operationalized by identifying them with specific properties of a time-series regression equation. Any judgment as to the occurrence of a party system trend or fluctuation should be based on an investigation of those dimensions of party systems in Western Europe which--according to our factor analysis--explain most of the variation. The concepts of trend and fluctuation may be introduced in relation to the equation:

PSDit = f (Time),

where PSDit, is party-system dimension i at election t.

The estimation of this regression equation on a time series results in values which identify the occurrence of a trend or a fluctuation. The concept of trend may be identified with a specific range of values of the significance level of the time-series equations describing the development in each country: a trend exists when the significance level is lower than .01. For each equation that fulfils this criterion on a trend, we look at the Beta-weights to get more information about the nature of the trend. The value of the Beta-weight reveals the direction of the trend, whether it is positive or negative.

The concept of fluctuation may be identified with the values for the standardized coefficient of variability, which the estimation of the same regression equation provides. We select the standardized CV-measure because the usual CV-measure is sensitive to a variation in the number of cases, i.e., number of elections in different countries. The standardized CV-measures are arrived at by dividing the CV-value with the maximum value of CV. The SCV varies between 0 and 100 percent, and we may select a range of SCV-values which can be identified as the indicator on the occurrence of a fluctuation: a SCV-value below or around 3-4 percent indicates no fluctuation while SC V-values over this range show fluctuations.


The occurrence of trends and the nature of a trend in party-system properties depend upon the period of time selected, in particular the choice of the starting point for the analysis. It is quite possible that a trend that occurs during one period may be followed by an opposite trend during the next period, which means that in the end little or no trend has occurred over the two periods of time. We investigate the amount and nature of trends in the party system dimensions for three periods: pre-1945, post-1945 and 1920-84. The division of the time period is based on the assumption that the Second World War may have had consequences for the structure of the party systems in Western Europe. Table 5:4 has the data for the pre-1945 time period as well as the post 1945 time interval.

 [Table 5.4 has been omitted]

Pre-1945 Trends

The national party systems vary in both the existence and the nature of trends. Change occurred in seven of the thirteen party systems that can be described by means of the party-system dimensions. The set of party systems that experienced trends during the pre-1945 period comprises: Denmark, the UK, Germany, Sweden, Switzerland, the Netherlands and Ireland. The magnitude of trends differs between these countries.

The Danish party system experienced trends in three dimensions: functional orientation, polarization and radical orientation. The increase in radical orientation is inversely related to the decline in functional orientation, because the steady growth of the Danish Social Democratic Party took place at the expense of traditional Bourgeois parties. Along with the increase in the electoral support for leftist parties came a rise in polarization.

In the UK, Sweden and Germany we find sharp Beta-weights for two party-system dimensions indicating considerable change in the national party system. The UK displays significant trends in polarization and radical orientation; this reflects the decline of the Liberal Party and the development of a two-party system characterized by the competition between right and left. The sharp rise in electoral support for the Social Democratic Party in Sweden comes out nicely on the measures of trend in radical orientation and functional orientation, the Beta-weight for radical orientation being positive and the Beta-weight for functional orientation being negative. The changes in the scores on functional orientation and polarization in the German party system is a function of the coming to power of the Nazi party; it expanded at the expense of the bourgeois parties and its rise heightened the level of polarization.

In Ireland and in the Netherlands two opposite trends occurred, increasing the amount of functional orientation in one country and decreasing the extent of functional orientation in the other. In Ireland the expansion of the Fianna Fail at the expense of the Fine Gael is noticed in the positive trend, whereas the decline of the traditional bourgeois parties and the rising electoral support for the religious parties explains the negative trend in the Netherlands. The party system of Switzerland is characterized by a change in polarization, reflecting the rising electoral support for the Socialists.

A typical feature of the development of the West European party systems during the inter-war period is hardly the lack of trends. On the contrary we find two trends that spelled out change: the increase in electoral support for leftist parties and the decline in support for traditional bourgeois parties. These trends neither are the only signs of change nor occur everywhere, but they should be noticed in a debate concerning the amount of change in the party systems of European democracies.

Post-1945 Trends

Regarding the question of the occurrence of trends it may be asserted that most national party systems have experienced trends in one or two of their party-system dimensions during the period after the Second World War. Actually only Austria and Sweden display no party system trends. In Belgium, Finland, Greece, Ireland, Italy and the UK the party systems show trends in no less than three dimensions, whereas we find two instances of party-system trends in Denmark and Germany. Even a short glimpse at the significance levels and the Betaweights of the regression equations summarizing the post-war development hardly give the impression of no change.

The party system of Belgium has experienced a profound reorganization since 1945; the fractionalization increased while the radical orientation and the polarization decreased, indicating the rise of ethnic alignments as a dominant characteristic of the party system. In the Federal Republic of Germany, the extent of radical orientation increased, whereas the amount of functional orientation diminished, at the same time as the general level of fractionalization declined. The movement of the German party system towards a large socialist party and a large religious party besides a small liberal party means a very different kind of party system compared with the remnants of the party systems of the Weimar Republic and the Third Reich still operating in the late Forties. The change in the Italian case stems largely from the expansion in the electoral support for the Communist Party, as the scores on both radical orientation and polarization display a positive trend. At the same time the level of volatility declined; it seems as if the electorate became more firmly organized along the left-right dimension. In Denmark we find two significant trends; on the one hand the degree of functional orientation decreased and on the other the extent of fractionalization increased. It is not difficult to interpret these change scores, as the Glistrup phenomenon has attracted traditionally bourgeois voters at the same time as other new parties were founded.

Concerning the data on the French system, the difference between the Fourth and the Fifth Republic comes out nicely; the amount of functional orientation rose indicating the coming of the Gaullist phenomenon, and the level of polarization increased, because of the rise of the Socialist Party at the expense of centre and left-wing extreme parties. Party-system change in Finland is a function of the increased fractionalization and polarization of the party system which result from the rise in electoral support for a number of discontent parties (Vennamo's SMP) belonging to the right wing. In Greece, the party-system experienced a trend in the amount of functional orientation because the centre union fell apart after the end of the dictatorship, while the amount of radical orientation increased due to the rise of the PASOK. There were actually two different types of party systems in Greece during that period: before the dictatorship the centre of gravity focussed upon the competition between two functional parties, the conservatives and the liberals, and after the dictatorship the centre of gravity became the left-right dimension.

Our measures of party-system change capture the re-entrance of the Liberal Party into the British party system; the extent of functional orientation is up, whereas the degree of radical orientation declined due to reduction in the electoral support for the Labour Party. The decline of Labour and the introduction of the Liberal-SDP Alliance also meant less polarization. We note a few other trends on the European scene. In the Netherlands, the trend after 1945 is opposite to the one that took place before 1945, the Liberal Party increasing at the expense of the religious parties. The degree of fractionalization diminished in Ireland, and this measure captures the tendency towards a three-party system in Ireland.

Party Systems Trends 1920-1984

We have hitherto looked at the existence, direction and magnitude of trends for two periods of time, pre- and post-1945, because it is an appropriate assumption that the Second World War functioned as a watershed in European politics, breaking up the normal modes of operation of political parties. We now inquire into the existence, direction and magnitude of party-system trends from roughly 1920 until the middle of the 1980s (Table 5:5).

TABLE 5.5 Party-system Change 1920-1984
(Significance Levels and Beta-weights)
Party systems
Functional orientation
Radical orientation











F R Germany

































United Kingdom

Note: Significance levels are given all cases whereas the Beta-weights are given in parentheses when the significance levels are below 0.010.

 Using the same measures we find that all party systems have experienced change in one or more dimensions. In two countries, Denmark and Austria, trends have occurred in no less than four or five dimensions; a few party systems display trends in three party-system dimensions: Finland and Italy. Typically, trends occur in the extent of radical orientation of the party systems, as no less than eight out of fourteen party systems have experienced that kind of trend; in seven countries- Austria, Denmark, France, Greece, Italy, the Netherlands, and Norway--there has been a positive change with an increase over time in the electoral strength of leftist parties. Belgium is the negative case where the Socialist Party has declined substantially. The second most important change dimension is the degree of functional orientation, which is characterized by the general decline in the electoral support for the traditional bourgeois parties--the conservatives, the liberals and the agrarians--in: Austria, Denmark, Germany, Finland, Italy, Norway and Switzerland. Trends also characterize fractionalization and polarization, the first kind of trend occurring in six nations and the second kind taking place in five nations. In some countries (Denmark, Finland and Switzerland) fractionalization is up, whereas in some (Austria, Germany and Ireland) it is down. Most nations that have experienced trends in the extent of polarization display an increase in that dimension, with the exception of Sweden. Four party systems show a trend in volatility, as it increased in Denmark and decreased in Austria, Ireland and Italy.


By using the SCV index on the five derived dimensions of the various party systems of Western Europe, we arrive at an overview of how various party systems differ in fluctuations as well as how each national system developed over time (Table 5:6).

[Table 5.6 has been omitted]

Fractionalization: It is not true that party systems have become generally more unstable in fractionalization. In some countries it is true: Belgium, Denmark, Germany and the Netherlands. However, we also find party systems which have become more stable: Austria, Ireland and Sweden. National party systems do vary in the extent of fluctuation Switzerland opposite obtains.

Functional Orientation: Where the post-war period is compared with the pre-war period we may establish that the fluctuation in functional orientation from election to election decreased in several countries including Finland, Greece, Ireland, Norway and Sweden. The opposite tendency is to be found in Belgium, France and the Netherlands. A few countries fluctuated much in functional orientation, -viz., Italy, Gerinusy, the Netherlands, Austria and France. In Switzerland, Finland and the UK the combined strength of traditional bourgeois parties has been stable.

Polarization: The extent of polarization varies little from election to election in all party systems with the exception of Germany, Greece, France, Italy and Belgium. The data indicate clearly that the extent of fluctuation in polarization decreased since the Second World War in most nations. There is only one case of an increase in variation from election to election: Finland.

Radical Orientation: The share of the vote for leftist parties varies extensively in Greece and Ireland, whereas there is a little fluctuation in radical orientation In countries like Austria, Finland, Switzerland and Sweden. It appear. that the amount of fluctuation in radical orientation decreased when the period post-1945 is compared with the period pre-1945. Actually, the overall impression is one of stability, though a few nations diverge from this impression.

Volatility: Volatility is a highly fluctuating dimension of party systems. There is a set of nations characterized by a high level of fluctuations: Italy, Germany, Austria and Switzerland. The general impression is one of a high level of variation in volatility in all the nations, but there is a set characterized by somewhat less fluctuation: the Netherlands and Sweden. A comparison of the pre-war figures with the post-war figures reveals that the amount of volatility is more fluctuating in the post-war period.

The overall impression which these data convey is that of stability in the sense of a lack of fluctuations. In most countries most of the party- system dimensions vary little from one election to another. There is one significant exception: volatility. The level of volatility in all systems is anything but stable; the extent of net electoral changes in the electoral strength of the political parties hovers considerably over time.

Party System Fluctuations: Overall Measure

We now proceed to an overall measure of party system stability on the basis of the results from the analysis of the extent of fluctuation in the five party-system dimensions. Table 5:7 presents the summing up of the SCV measures for each country for three periods.

TABLE 5.7 Party-system Fluctuations: Overall Measures
(Expressed as T-scores)
Party system
Pre- 1945







F.R Germany




















United Kingdom

Note: The overall measures have been arrived at by aggregating and standardizing the CV scores for each period and each party-system dimension.

There are significant variations in the occurrence of fluctuations in he national party systems in Western Europe; look at the difference between the maximum and the minimum values, Germany with 64.4 and Sweden with 42.0. However, these aggregations of the measures of the extent of fluctuations in party-system dimensions for three periods have shortcomings. They may fail to recognize changes in party system fluctuation for small spans of time like five-year periods. They may present too simplistic a view of fluctuation, because some national party systems may show differing amounts of fluctuation in various party-system dimensions, which differences the overall measure fails to catch.

Party-system fluctuation as gauged by the overall measure mmarizing the occurrence of fluctuations of the various party-stem dimensions is a function of volatility. The level of volatility explains party-system fluctuation and we may use this relationship between volatility and party system fluctuation to derive a scale that measures party-system fluctuation, the mean value of volatility for each five-year period. Table 5:8 covers the cross-sectional variation as well as the longitudinal variation in party system volatility.

From the Table 5:8 it appears that party-system volatility in Western Europe varies with the period of time selected. The amount of volatility is high after the First World War and before and after the Second World War. From 1950 and up until 1970 there was a general decrease in volatility compared with earlier periods of time. Since the early Seventies volatility increased in general, which has been noticed by several scholars.


The party systems of European democracies are different. To account for the differences, one needs a five-dimensional model covering:

(1) Fractionalization, i.e., the variation in the number and strength of the constituent parts of the party systems

(2) Functional orientation, i.e., the variation between traditional bourgeois parties and religious and ethnic parties

(3) Polarization, i.e., the variation in the ideological distance between the political parties along the right-left scale

(4) Radical orientation, i.e., the variation in the strength of leftist parties

(5) Volatility, i.e., the variation in net mobility between political parties.

A party system is a system of elements with relationships. We have identified five party-system properties that explain most of the variation among the set of party systems studied. Some of these properties refer to the elements of party systems (functional orientation and radical orientation), whereas the others refer to relationships (fractionalization, polarization and volatility).

The basic problem in the study of West European party systems concerns change. Our findings are summarized in Figure 5:1. Since it is not clear how the concepts of change and stability in relation to the concept of party system are to be defined or operationalized, we have substituted the concepts of party-system trend and fluctuation for these ambiguous terms. The findings indicate that the widely accepted hypothesis that West European party systems are characterized by stability, i.e., no change is not in accordance with the data. Actually, more than half the party systems score high or medium on the trend scale when the time period since the democratization of the polities is considered. It is true that there are fewer trends occurring after the Second World War. Moreover, the various party systems differ in the amount of fluctuation in both time periods.

FIGURE 5.1: Party-system Trends and Party-system Fluctuations
1920-1984 and post-1945

The variation in trends and in fluctuation do not co-vary. There are countries which experienced few or no trends but are characterized by fluctuations. There are also countries that display trends in several party-system dimensions but are not characterized by fluctuations. Regarding 1920-84 and the period after the Second World War, it is evident that one may find seminal trends in West European party systems and also that some of these party systems are characterized by fluctuations. The party-system stability hypothesis, presented in Chapter 3, must be qualified, if not rejected.

We have dealt extensively with the political parties in Western Europe and their relationships to social cleavages. Moreover, we have analysed the various national party systems at length. It is time to move on to the next level of analysis, the governmental level. We may assume that the structuring of polities as well as the occurrence of issues in national policy-making have an impact on political stability.