Electoral Overoptimism among Political Elites: Evidence from a PR System

This study makes a three-fold contribution to the growing literature on politicians’ cognitive biases. First, we introduce a new, probabilistic measurement of politicians’ overoptimism about their party’s prospects of winning government office, devised for PR systems. Second, we propose an argument for why political leaders—although known to be positively selected on cognitive ability—should be more prone to optimism bias than non-leaders. Third, we evaluate this argument using original survey data from Swedish local governments. We document substantial overoptimism, particularly among opposition politicians and those in elite positions. We furthermore provide quasi-experimental evidence suggesting that political leaders’ overoptimism is partly due to confirmation bias when interpreting voter preferences, as they are only more prone to optimism bias than non-leaders when their party has gained in recent polls. The observed overoptimism has implications for policy-making by potentially deterring opportunistic, myopic policies aimed at short-term vote maximization at the expense of long-term priorities.