10.7910/DVN/HBL8GTMongrain, PhilippePhilippeMongrainVox Pop LabsKuraishi, AnamAnamKuraishi0000-0003-3222-807Xhttps://ror.org/05b5x4a35Soontjens, KarolinKarolinSoontjens0000-0002-4615-510XUniversity of AntwerpWalgrave, StefaanStefaanWalgrave0000-0003-1814-1015University of AntwerpHarvard Dataverse2026Social SciencesMongrain, PhilippePhilippeMongrain2026-01-302026-02-051251274933574615262598404188548104878149142378851045813570215679text/x-stata-syntaxtext/x-stata-syntaxtype/x-r-syntaxtype/x-r-syntaxtype/x-r-syntaxtype/x-r-syntaxtype/x-r-syntaxtype/x-r-syntaxtype/x-r-syntaxtext/x-stata-syntaxapplication/vnd.openxmlformats-officedocument.spreadsheetml.sheettext/x-stata-syntaxtext/x-stata-syntaxtext/x-stata-syntax1.0CC0 1.0This study explores politicians' expectations of future election outcomes, the accuracy of these predictions, and the role of wishful thinking in shaping such electoral estimations. Before the 2024 regional elections in Belgium, local politicians were surveyed to gather their views on the likelihood of regional political parties winning or losing seats, as well as the probability of these parties being part of the next government coalition. To benchmark politicians' predictions and the accuracy thereof, similar survey evidence was collected among citizens in a parallel survey. Our findings reveal that both politicians and citizens are strongly influenced in their electoral predictions by wishful thinking, often leading them to overestimate the likelihood of favourable outcomes for their preferred party. Interestingly, we found almost no difference in how partisan identities shaped expectations and the accuracy of forecasts between these two groups. This suggests that even politicians, whose roles often require them to be more strategically attuned to electoral dynamics, are just as susceptible to cognitive biases as the general public.