Disproportional representation

Scotland - Poverty linked to spoiled ballots
A study into the Scottish election voting fiasco has found the highest proportion of rejected constituency votes came in the most deprived areas. The probe, by the University of Strathclyde, was triggered by the chaos which saw more than 140,000 spoiled papers in the May poll. It also found that more votes were discounted in areas where there were a larger number of list candidates.

Clearly it's not poverty, as such, which is the issue but the ability of voters to understand complex directions. Poor schooling, poor educational attainment, poverty, poor housing - it was voters from these backgrounds that had the greatest trouble understanding the badly designed voting system. And that's leaving aside the many more constituents who didn't bother to vote at all. Once the decision had been made to hold the local and assembly elections on the same day and using a single-paged ballot it was inevitable that complexity alone would lead to spoiled papers and that the disadvantaged members of society would be disproportionally affected.