Alexander C. Tan, "Party Change and Party Membership Decline: An Exploratory Analysis," Party Politics, 3 (July 1997), 363-377.

First Paragraph:
More than 80 years ago, Robert Michels, in his seminal book Political Parties, argued that party membership size, and particularly growth in party membership, has a definite effect on organizational structure and the distribution of power within the organization (Michels, 1962: 65). Evidence from studies of other forms of complex organizations consistently shows a statistically significant relationship between size and other organizational attributes.

Figures and Tables:
Table 1: Levels of party membership by party (thousands).
Figure 1: Organizational complexity, 1960-90.
Table 2: Regression of party size, professionalism and state subsidy on organizational complexity (estimated coefficients).
Figure 2: Centralization of power, 1960-90.
Table 3: Regression of party size, professionalism and state subsidy on centralization of power (estimated coefficients), Labour Party.

Last Paragraph:
Much remains to be done to increase our understanding of the impact of declining party membership size on party organizations. Since the analysis in this study is necessarily only exploratory, future work should be directed towards addressing the issues raised here (and collecting data for such research) so as to accumulate more evidence regarding the impact of declining party membership size.