Wisdom of the crowds forecasting the 2018 FIFA Men's World Cup

TL;DR

This paper investigates how crowdsourced forecasts can effectively predict outcomes of the 2018 FIFA World Cup, demonstrating that aggregated crowd predictions can rival statistical models in accuracy.

Contribution

It introduces a novel online contest platform for crowd predictions and evaluates the effectiveness of various aggregation methods against traditional models.

Findings

Crowd-based forecasts achieved high accuracy.

Some aggregation methods outperformed simple strategies.

Crowd wisdom proved competitive with statistical models.

Abstract

The FIFA Men's World Cup Tournament (WCT) is the most important football (soccer) competition, attracting worldwide attention. A popular practice among football fans in Brazil is to organize contests in which each participant informs guesses on the final score of each match. The participants are then ranked according to some scoring rule. Inspired by these contests, we created a website to hold an online contest, in which participants were asked for their probabilities on the outcomes of upcoming matches of the WCT. After each round of the tournament, the ranking of all users based on a proper scoring rule were published. This paper studies the performance of some methods intended to extract the wisdom of the crowds, which are aggregated forecasts that uses some or all of the forecasts available. The later methods are compared to simpler forecasting strategies as well as to statistical prediction models. Our findings corroborate the hypothesis that, at least for sporting events, the wisdom of the crowds offers a competitive forecasting strategy. Specifically, some of these strategies were able to achieve high scores in our contest.