Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
We test the effect of an important electoral reform implemented in Italy from 1993 to 2001, that moved the system for electing the Parliament from purely proportional to a plurality rule (for 75% of the seats). We do not find any effect on either the number of parties or the stability of governments (the two main objectives of the reform) that remained unchanged at their pre-reform level.