Investigating bias with ‘ghost games’

This exercise is a part of Educator Guide: When Fans Are Away, Home Teams Lose Their Sway / View Guide

Directions for teachers: Ask students to read the online Science News article “‘Ghost games’ spotlight the psychological effect fans have on referees,” which describes research into a phenomenon in sports known as home field advantage, and answer the following questions. A version of the story, “When fans are away, home teams lose their sway,” appears in the September 25, 2021 issue of Science News.

1. What does the term ‘ghost games’ mean, according to the Science News article?

Ghost games, as defined by the Science News article, are sports games played in empty or nearly empty stadiums.

2. Why did sports teams play in ‘ghost games’?

Soccer teams played in empty stadiums due to pandemic restrictions — officials limited or banned spectators from attending games.

3. What is home field advantage?

Home field advantage is the phenomenon where sports teams tend to do better when competing in their own stadium.

4. What is one scientific claim made by the scientists as described by the article?

Fans influence home field advantage.

5. What evidence supports the scientists’ claim? Be sure to state where the evidence comes from.

Scientists compared the outcomes of European soccer games from the 2018–2019 season with game outcomes from the fan-limited 2019–2020 season. During the “ghost game” season, home team win rate decreased by 8.3 percentage points (from 48.1 percent to 39.8 percent) while the loss rate increased by 8.4 percentage points (from 27.6 percent to 36 percent). And foul calls against home teams increased by 26 percent compared with just 3 percent for away teams.

6. What reasoning is given for why the evidence supports the claim?

Referees exhibit a bias toward home teams by issuing those teams fewer foul calls when fans are present compared with when fans are absent. That bias may influence the outcomes of soccer matches in the home teams’ favor.

7. How might the research be useful to referees, according to sports psychologist Michael Leitner?

Leitner hopes that the research can help referees become more aware of their biases and train against those biases.

8. What’s another question that you could study using data from ‘ghost games’?

Student answers will vary. A student might say: Does fan presence influence the average intensity of athletes’ performance?

Sign up if you’re interested in receiving free Science News magazines plus educator resources next school year. The Society for Science’s Science News in High Schools program serves nearly 5,000 public high schools across the United States and worldwide.

Learn More