Problem 1 [30 Points]

Below are a series of causal statements about recent events (disclosure: these statements do not reflect the instructor’s views). For each event, please do the following:

  1. The US women’s gymnastics team lost the gold medal in the all-around competition at the 2021 Olympics because Simone Biles dropped out of the competition.
  1. The Democratic Party nominated Kamala Harris to be its 2024 presidential candidate because of Joe Biden’s poor performance in the first presidential debate on June 27, 2024.
  1. The Supreme Court ruled in Dobbs v. Mississippi that Roe v. Wade was wrongly decided and that there is no constitutional right to abortion because Ruth Bader Ginsburg died in September 2020.
  1. Will Smith was banned from Academy of Motion Picture Arts and Sciences events for 10 years because he slapped Chris Rock at the 2022 Academy Awards ceremony.
  1. The Kansas City Chiefs won Super Bowl LVIII because Taylor Swift made it back from Japan in time to cheer on her boyfriend, Travis Kelce.

Problem 2 [40 Points]

Please read “Voter Mobilization 101: Presidential Campaign Visits to Colleges and Universities in the 2016 Election” by Christoper J. Devine (, April 2019, 261-266) and answer the following questions about its research design.

Internal Validity (Causal Credibility) The study attempts to establish a causal relationship between campaign visits and voter turnout. However, confounding factors could undermine internal validity.

Potential issues:

Selection bias: Candidates tend to visit campuses in areas where they are already competitive, meaning that observed effects might not be solely due to the visits. Reverse causality: Higher expected turnout might have attracted campaign visits rather than the other way around. Omitted variable bias: Other mobilization efforts (e.g., local activism, social media campaigns) could explain increased turnout rather than the campaign visits alone. The study likely uses statistical controls (e.g., regression models) to address these concerns, but isolating the true effect remains challenging.

External Validity (Generalizability) The study focuses on a specific election (2016) and a specific demographic (college students), which limits generalizability.

Problem 3 [30 points]

Works of fiction (books, movies, TV shows) often explore alternate histories to consider how their plots would have differed if for one difference earlier on in the work (or in the time before the work picks up). Identify one such instance in a work of fiction and please do the following (a paragraph or less will suffice for each part):