Effects of Part-time Work on Productivity, Wages and Profits in the Belgian Private Sector : An In-depth Microeconometric Analysis of the Roles of Gender, Sectors and Intensity of Value Creation

This thesis analyses the impact of part-time work on productivity (Chapter 1), wages (Chapter 2) and profitability (Chapter 3). Relying on a rich panel dataset of 2,273 Belgian firms observed from 2011 to 2019 (1223 firms in Chapter 3), we measure firm outcomes directly and investigate the role of more granular categories of part-time employment by linking part-time status with key moderating variables.
Chapter (1) relies on SYS-GMM estimators derived from seven relationships, which enable to control for the potential state dependence of firm productivity, simultaneity between firm’s productivity and the composition of its workforce and constant unobserved heterogeneity between firms, while including a wide range of covariates. Our original approach, where labour contracts are interacting with both gender and sector of activity, reveals that female part-timers and full-timers (to a lower extent) working in services sector are less productive, in other words that being a woman working in the service sector harms productivity to a greater extent in the case of part-time contracts, even though their sector of employment and gender are more significant factors than their employment contract.
In Chapter (2), after controlling for the dynamics in the wage adjustment process, endogeneity bias and time invariant workplace characteristics, our SYS-GMM results indicate that part-time workers as a whole suffer a wage disadvantage. By originally deepening the analysis at the level of the interactive roles of gender and sector, we find that women working part-time in services suffer a triple wage penalty. A lesser double penalty is also estimated for other categories of female workers who are ‘only’ penalized by working part-time or in the services sector, with the former effect appearing to slightly outweigh the latter. We also highlight that, overall, around 4 out of 5 women suffer wage penalties, while men do not suffer any penalty, regardless of their labour contract or the sector in which they work.
Chapter (3) provides an in-depth empirical analysis of the impact of part-time work in the service sector on labour productivity and wage cost and, ultimately, on their gap, i.e. profit. Based on appropriate modelling and estimation techniques, our preferred SYS-GMM results generally support a standard profit-maximisation condition. Indeed, employers manage their workforce according to their economic environment in such a way that profits do not differ between the categories considered in an original way, based on the labour contract in interaction with gender and the intensity of value creation by firms, with the exception of male part-time work, which has a slightly negative effect. From the workers’ perspective, this also means that workers are generally paid fairly according to their productivity in these large firms where unions play an important role, with productivity being therefore the main determinant of their wages.