Using polls to forecast popular vote share for US presidential elections 2016 and 2020: An optimal forecast combination based on ensemble empirical model

Abstract

This study introduces the Ensemble Empirical Mode Decomposition (EEMD) technique to forecasting popular vote shares in general elections. The technique is useful when using polling data. Our main interest in this study is shorter- and longer-term forecasting and, thus, we consider from the shortest forecast horizon of 1-day to three months ahead. The EEMD technique is used to decompose the election data for the two most recent US presidential elections; 2016 and 2020. Three models, Support Vector Machine (SVM), Neural Network (NN) and ARIMA models are then used to predict the decomposition components. Subsequently, the final hybrid model is constructed by comparing the prediction performance of the decomposition components. The predicting performance of the combination model is compared with the benchmark individual models: SVM, NN, and ARIMA. Finally, this is also compared to the single prediction market IOWA Electronic Markets. The results indicate that the prediction performance of combined EEMD model is better than that of the individual models.

Keywords:

• Forecasting popular votes shares
• electoral poll
• forecast combination
• hybrid model
• support vector machine

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 Please note that the 2020 presidential polling data is only available from the 1 September 2019. Further details and breakdown of the data is found in: https://www.realclearpolitics.com/epolls/2016/president/us/general_election_trump_vs_clinton-5491.html and https://www.realclearpolitics.com/epolls/2020/president/us/general_election_trump_vs_biden-6247.html.

2 Due completeness and availability, we use the Last Price daily quote. Further details and breakdown of the data is found in: https://iemweb.biz.uiowa.edu/markets/.