Applying Prospect Theory to EU referendum voting behaviour
: explaining irrational choice and turnout in the Brexit referendum

Student thesis: Doctoral ThesisDoctor of Philosophy


This thesis examines how prospect theory can help to explain voter’s choice and turnout in EU referendums. It intends to propose prospect theory as a challenge to the EU referendum school of utilitarian expectations while at the same time it aspires to contribute to other EU referendum schools such as EU referendum campaigns, substantive issues and identity politics. I argue that the inductive origin of prospect theory may not necessarily be an impediment to empirical testing, which can be achieved via rigorous experimental designs and survey experiments with representative samples. Three survey experiments in cooperation with Ipsos Mori UK were carried out weeks before Britain’s 2016 EU referendum to test the hypotheses derived from prospect theory. On the one hand, the results show that prospect theory’s reference point could not be confirmed for the entire electorate but could be an explanation for outcomes for specific subsamples (i.e. the unmarried, unemployed, and parents). In addition, Quattrone and Tversky’s (1988) ratio-difference principle could not be confirmed. On the other hand, as regards voter’s turnout, the results show that the British voter did fall for the voter’s illusion as set out by Quattrone and Tversky (1986); a paradox to the rational voter’s model, considering the voter’s single vote to be diagnostic of millions of other votes. Thus, British voters were more likely to turn out when informed that the undecided voters will determine the outcome of the referendum, a result that deviates from the voter’s rational model. While the voter’s illusion phenomenon is found to be more influential for the unmarried, it wasn’t confirmed for non-parents, employed and female voters. Meanwhile, the result of a lab experiment didn’t abide by the conventional level of statistical significance but showed tentative support (p<.1) for the suggestion that the voters in the EU referendum regarded Leave as a risky decision while Remain as the risk-averse one. The latter may reaffirm though the importance of risk in the EU referendum which in principle has a core essence in prospect theory. All in all, considering the thesis’ confirmed and null results this PhD aspires to suggest insights from prospect theory as a possible alternative theoretical model for voter’s choice and turnout in Britain’s EU referendum of 2016, sitting at the intersection of the other EU referendum schools. Naturally, future work may test the thesis’ results further in order to evaluate prospect theory, in conjunction with other relevant literature, as a potential angle of EU referendum voting.
Date of Award1 Jan 2022
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorLee Savage (Supervisor) & Ruben Ruiz-Rufino (Supervisor)

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