Comparative research is always a challenge. However, it is also necessary if we are to develop robust interpretations and encompassing theories (Hyman, 2001), with a view of displaying both similarities and differences, as well as identifying ‘best practice’ (Ledwith and Hansen, 2013). The two studies presented in this book approach international comparison in different ways. The first, on women's underrepresentation in trade unions, uses a ‘career’ methodology to analyse the variation in ‘inequality regimes’ (Ackers, 2006) across two countries. The second proposes a socio-historical analysis of legal mobilizations (Lehoucq and Taylor, 2020) in favour of equal pay in the UK as an example to draw useful lessons for other national contexts (notably France) on the effectiveness of mobilizing the courts as a union repertoire of action. In doing so, both studies offer different contributions to (comparative) research in industrial relations.

Designing a longitudinal case study

The first contribution of this research is methodological. Our aim in this comparative endeavour was to overcome some of the difficulties encountered in comparative research on industrial relations (Hyman, 2001), and to avoid a deterministic and overarching perspective investigating institutions and structures (for example, industrial relations systems, gender equality regimes) at the expense of social processes (for example, social construction of gender inequalities). At the same time, while previous research has shown that there is a universalism in the way women are treated in the workplace and a strong resilience of the gendered order over time (Kirton and Healy, 2013a), scholars have argued for contextually and/or historically grounded analysis as a means of understanding the structure and dynamics of ‘inequality regimes’ (Acker, 2006). Studies have established that several institutional characteristics contribute to the variations in the extent to which equality is achieved in different union contexts; they include size (Kirton, 2015), the internal union labour market (Guillaume and Pochic, 2011) and internal democracy (Healy and Kirton, 2000; McBride, 2001), the framing of gender equality strategies (more or less feminist and/or intersectional), and the articulation of class and gender (Dean 2015; Guillaume, 2018a). Moreover, socio-historical studies have highlighted the fact that the union representation of women is inscribed in and should be understood in the context of specific social, economic, and institutional configurations.