This book provides a picture of the current economic research on trade unions in an edited collection of recent papers, both theoretical and empirical, concerned with the quantitative analysis of trade unions' behaviour and impact. In particular it compares the results of the most recent theoretical developments with empirical studies in each area of research. The papers are grouped into three sections. The first one is devoted to unions' objectives and membership. The papers included in this section show how to aggregate individual's preferences and how various forms of aggregration can influence membership. The second section analyzes the different contractual set-ups and how they influence the final allocation of the labour market. Furthermore, it shows how a bargaining model can help in the explanation of strikes. The last section introduces the debate on the macroeconomic effects of trade unions on both long run equilibria and stabilization policies. In all sectors, empirical papers follow the theoretical ones in order to ascertain how theory is able to explain the major economic facts.

Over the 1980s unions have lost about 5 million members in OECD countries. The proportion of unionized workers is increasing in the services, public sector and among women. Today, almost two out of five union members are employed in the public sector. Wide differences remain in the levels of unionization in diverse countries, while in the United States, France and Spain union members account now for little more than 10% of the labour force, in the Nordic countries (Sweden, Finland and Denmark) the corre'sponding figure is between 75 and 85%. In general, rates have been higher in Europe than in North America. Economic analysis is paying increasing attention to these developments and to their policy implications (Edwards, Caronna and Todling, OCDE 1991). Recent progress in economic theory has enabled some light to be cast on the determinants of unionism, on the other hand, efforts aimed at coming to grips with the economic reality of unions have significantly contributed to theoretical advancement by extending and modifying conventional microeconomic wisdom. The reader of this volume will judge whether the insight gained is sufficient, or - as a recent survey concluded ~ the problem has proved to be virtually intractable (Johnson, p. 24). These can be grouped under three headings, corresponding to the three parts of the volume, which will be illustrated in the Introduction.