Here’s a null result I’ve long wanted to share: The level of descriptive representation seems unrelated to population size. More specifically, the share of women in national legislatures and the share of ethnic minority groups in national legislatures (relative to their size in the population) does not correlate substantially with the overall population size. I’ve looked into this a few years back after receiving comments that the nature of political representation could be expected to be different in small countries (microstates). I’m still unsure why this would be the case — except that in really small chambers including an additional woman adds much to the share of women.
In their 2014 article, Leslie Schwindt-Bayer and Peverill Squire show that the political power of legislatures can affect gender representativeness of legislatures. In the article they discuss likely mechanisms and suggests that the same result applies to ethnic groups. The argument is that in a legislature with more professional power, need to provide representatives with incentives to compensate for their investments like long sessions. These incentives, in turn, encourage incumbents to preserve their seats and discriminate against under-represented groups. Sounds reasonable enough, but ever since collecting information on the ethnic composition of legislatures worldwide, I have been keen to empirically check such claims.
I did so using the spreadsheet from the DICE Database and my own data on ethnic representation. This gives me 35 countries to have a quick look at the claim: there is no such correlation among the countries examined.
Ruedin, Didier. 2009. ‘Ethnic Group Representation in a Cross-National Comparison’. The Journal of Legislative Studies 15 (4): 335–54. doi:10.1080/13572330903302448.
———. 2010. ‘The Relationship between Levels of Gender and Ethnic Group Representation’. Studies in Ethnicity and Nationalism 10 (2): 92–106. doi:10.1111/j.1754-9469.2010.01066.x.
———. 2013. Why Aren’t They There? The Political Representation of Women, Ethnic Groups and Issue Positions in Legislatures. Colchester: ECPR Press.
Schwindt-Bayer, Leslie, and Peverill Squire. 2014. ‘Legislative Power and Women’s Representation’. Politics & Gender 10 (4): 622–658. doi:10.1017/S1743923X14000440.