Skip main navigation

Potential Pitfalls for Election Prediction

In this video Professor Chris Hanretty gives Professor Michael Spagat his short list of the main things that can go wrong with election prediction.

This interview nicely complements my video from step 2.14, but with an exclusive focus on election prediction. Here’s my summary of the key points, which mix together both old and new ideas for us.

  1. Election polls often measure the wrong thing since they are often national even when elections are decided constituency by constituency.
  2. Predicting who will vote is crucial for election prediction but hard to do.
  3. Respondents might lie, or just be unintentionally inaccurate, about various things such as their likelihoods of voting or which candidates they support. It is often claimed, for example, that there is a “shy Tory effect” in UK politics whereby some conservatives, especially young ones, hide their leanings.
  4. For various reasons you may not be able to complete interviews with many people who have been randomly selected into your sample. For example, some people may not pick up the phone or may hang up when they learn that a pollster is on the line.


Is problem 4 really such a big issue?

If, for example, a pollster wants a sample of 2,000 people and is able to complete 1 interview out of every 10 attempts then can’t she just attempt 20,000 interviews with a goal of taking 2,000 of these interviews to completion?

This article is from the free online

Survival Statistics: Secrets for Demystifying Numbers

Created by
FutureLearn - Learning For Life

Reach your personal and professional goals

Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates.

Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas.

Start Learning now