The Accuracy of Numbers.lk Polls in Predicting Sri Lanka's Presidential Election

For the second presidential election in a row, Numbers.lk has demonstrated remarkable accuracy in polling Sri Lanka’s electorate, successfully predicting the race’s outcome within the margin of error for the top two candidates. Numbers.lk’s final poll, conducted between the 9th and 16th of September, and published on the 18th, estimated Anura Kumara Dissanayake (AKD) would receive 40% of the vote, while Sajith Premadasa was predicted to secure 29%.

📊 Final NumbersLK pre-election poll results are in! 🇱🇰 🗳️

🧭 AKD - 40%
☎️ Sajith - 29%
🐘 Ranil - 25%
🌷 Namal - 3%
❔ Undecided - 1%

Sample: 5,335 adults
Period: Sep 9-16
Margin of error: +/- 5.0%

more: https://t.co/wB5Oki9x7b pic.twitter.com/m5o6oJaBCT

— Numbers.lk (@numberslka) September 18, 2024

Actual Results:

1. Anura Kumara Dissanayake: Poll: 40% - Actual: 42.31%
2. Sajith Premadasa: Poll: 29% - Actual: 32.76%

These results are well within the margin of error of +/- 5%.

Polling vs. Prediction: Understanding the Difference

The distinction between polling and predicting election outcomes is crucial. Polls provide a snapshot of public opinion at a specific moment, capturing voters' preferences during the polling period. In contrast, predictions are broader estimates, often based on various techniques, models, and sometimes even gut feelings. While anyone with access to sufficient information can attempt a prediction, polling relies on scientifically gathering data from representative samples of the electorate.

In the case of Numbers.lk’s final poll, the results diverged slightly from the actual outcome. This is not uncommon, as polls capture voter sentiment during the polling window, while actual voting behavior can shift, particularly in the final days leading up to the election.

The Last-Minute Shift in Voter Behavior

One well-documented trend is the phenomenon of voters shifting their support from third-party or independent candidates to the top contenders in the final days before the election. This behavior is seen globally, where voters who initially support a third-party candidate may ultimately switch to one of the top two candidates in an effort to prevent a candidate they oppose from winning.

This pattern may have played a role in the 2024 Sri Lankan presidential election as well. In our final poll, Ranil Wickremesinghe was projected to have 25% support, but he ultimately received only 17.27% of the vote. The fact that both Anura Kumara Dissanayake (AKD) and Sajith Premadasa outperformed their polling numbers by 2-4 percentage points suggests that a portion of voters may have shifted their support from Ranil Wickremesinghe to one of the top two candidates in the final days.

This discrepancy between polling and actual results might not indicate a polling error, but rather the possibility of voters changing their minds at the last moment. Our poll was conducted between the 9th and 16th of September, while the election took place on the 21st.

This dynamic can be seen in numerous elections worldwide, including U.S. presidential races, as highlighted in research by the Pew Research Center.