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QAPEC Feature Publications

Citizen Forecasting 2020: A State-by-State Experiment

Andreas E. Murr and Michael S. Lewis-Beck

The leading approaches to scientific election forecasting in the United States consist of structural models, prediction markets and opinion polling. With respect to the last, by far the dominant mode relies on vote intention polling, e.g., “If the election were held tomorrow, who would you vote for?” However, there exists an abiding opinion polling strategy that shows a good deal of promise—citizen forecasting. That is, rather than query on vote intention, query on vote expectation, e.g., “Who do you think will win the upcoming election?” This approach has been pursued most extensively in the United Kingdom (Murr 2016) and the United States (LewisBeck and Tien 1999). Recent performance evaluations have shown that in the United Kingdom vote expectations clearly offer more predictive accuracy than vote intentions (Murr et al. forthcoming) and that in the United States vote expectations appear to be superior to an array of rival forecasting tools (Graefe 2014). However, the timing of the data collection has forced most of the studies using citizen forecasts to forecast elections ex post, i.e., after they occurred. Indeed, to date, there are only two ex ante citizen forecasting papers to have appeared before a national election (Lewis-Beck and Stegmaier 2011; Murr 2016). Both these efforts forecasted British General Elections, with Murr (2016) relatively most accurate among 12 academic forecasts (Fisher and Lewis-Beck 2016).

Fundamental utilitarianism and intergenerational equity with extinction discounting.

Graciela Chichilnisky, Peter J. Hammond & Nicholas Stern

Ramsey famously condemned discounting “future enjoyments” as “ethically indefensible”. Suppes enunciated an equity criterion which, when social choice is utilitarian, implies giving equal weight to all individuals’ utilities. By contrast, Arrow (Contemporary economic issues. International Economic Association Series. Palgrave Macmillan, London, 1999a; Discounting and Intergenerational Effects, Resources for the Future Press, Washington DC, 1999b) accepted, perhaps reluctantly, what he called Koopmans’ (Econometrica 28(2):287–309, 1960) “strong argument” implying that no equitable preference ordering exists for a sufficiently unrestricted domain of infinite utility streams. Here we derive an equitable utilitarian objective for a finite population based on a version of the Vickrey–Harsanyi original position, where there is an equal probability of becoming each person. For a potentially infinite population facing an exogenous stochastic process of extinction, an equitable extinction biased original position requires equal conditional probabilities, given that the individual’s generation survives the extinction process. Such a position is well-defined if and only if survival probabilities decline fast enough for the expected total number of individuals who can ever live to be finite. Then, provided that each individual’s utility is bounded both above and below, maximizing expected “extinction discounted” total utility—as advocated, inter alia, by the Stern Review on climate change—provides a coherent and dynamically consistent equitable objective, even when the population size of each generation can be chosen.