Medill’s Subscriber Data Analysis: How We Reached Conclusions

The Spiegel Research Center at Northwestern University analyzed 13 terabytes of data from the Chicago Tribune, San Francisco Chronicle and Indianapolis Star for its study, which was conducted in the fall of 2018 as part of the Medill Local News Initiative.

Data scientists at Spiegel integrated audience data and subscriber information from each of the three news organizations. This allowed researchers to trace anonymized, individual behaviors of people who kept and cancelled digital subscriptions. This cross-platform data integration by Northwestern data scientists provided a unique, vivid portrait of digital news consumption habits of local subscribers.

Spiegel, which is affiliated with Northwestern’s Medill School of Journalism, Media, Integrated Marketing Communications, used established statistical methods to measure the impact of readers’ behavior on subscription retention and express it numerically. Numbers that were negative suggested a correlation with subscription retention; those that were positive suggested a reverse correlation. Numbers above 2 in either direction were considered statistically significant.

All three news organizations showed strong retention linked to a regular habit, with the Chronicle at -10.3, the Star at -8.5 and the Tribune at -5.5.

What Spiegel Research Director Ed Malthouse calls “extent” (page views per day visited) and “depth” (time spent per page view) showed a correlation with churn for the Chronicle and the Star (13.5 and 2.1 for the Chronicle and 2.6 and 3.6 for the Star). For the Tribune, the figures were -0.8 and 1.6, indicating no statistically significant correlation either for or against retention.

Malthouse explained it this way: “The numbers are Z statistics of the slopes from a logistic regression model. A value of 0 means that a predictor has no effect on churn. Positive values mean that more of the predictor is associated with a higher chance of churning. Negative values mean that as the value of the predictor increases, the chance of churning goes down (i.e., is more likely to be retained).

“When we evaluate slopes, we commonly test the null hypothesis that the slope is 0, meaning that the variable has no effect. If we use the 95 percent confidence level, which is pretty common, then a Z statistic greater than 2 or less than -2 is called ‘statistically significant from 0.’ Values greater than 2.576 or less than -2.576 are called ‘highly statistically significant.’ Values greater than 3.29 or less than -3.29 are called ‘very highly significant.’”

The analysis included data from the main Chronicle subscriber site (sfchronicle.com, not sfgate.com) from Sept. 17, 2017, to Oct. 16, 2018. For the Tribune, the data was from Oct. 1, 2015, to July 19, 2018. For the Star, it was from June 30, 2016, to Aug. 5, 2018.

As a follow-up to this study of the Tribune, Chronicle and Star data, Spiegel is now analyzing subscriber behavior data at small and mid-sized news outlets in the Midwest.

Latest Posts

  • Sobering Reality for News Outlets: Your Readers May Be Elsewhere 99% of the Time

    Here’s a question for local news producers: What are your readers doing when they’re not visiting you? That’s the question asked by Northwestern University’s Spiegel Research Center in an eye-opening study of three metro news websites based on data from the media analytics company Comscore. And it’s a particularly relevant question because the study showed that the three news sites commanded less than 1 percent of their desktop users’ total digital time. The study, conducted...

    Continue Reading

  • Medill Teams With German Foundation for Global Seminar on Local News

    The Medill Local News Initiative and Germany’s Konrad-Adenauer-Stiftung foundation will host the Global Seminar on Local News, a June conference in Chicago to discuss worldwide challenges to local journalism and their impact on democracy. The seminar will feature presentations by news executives from Bulgaria, Nigeria, Mexico and Germany as well as influential U.S.-based voices on the crisis in local news. The June 24-26 event is invitation-only, but video of the main discussions on June 25...

    Continue Reading

  • Knight Lab’s Class Brings Design Principles to Local News

    A new Northwestern University class called Design for Local News isn’t trying to make minor tweaks in the current media environment. It’s going straight to the question of what information the public needs and starting there to invent new products. “It’s like a Zen beginner’s mind, a ‘first principles’ sort of thing. Pick your metaphor,” said Associate Professor Zach Wise. As local news outlets suffer from a disrupted business model that has led to widespread...

    Continue Reading

  • Medill’s Franklin on Why Local News Outlets Aren’t Jumping in Apple’s ‘Magic Mixer’

    The recent launch of Apple News Plus is the biggest test yet for news bundling—the idea of selling access to a wide variety of news sources through one platform at one price. Apple News Plus costs $9.99 a month for more than 300 titles, mostly magazines but also a few newspapers such as the Wall Street Journal and the Los Angeles Times. In general, local news organizations have not signed on, put off by Apple’s...

    Continue Reading

  • The ‘eHarmony of Political Coverage’ and Other Local News Innovations Medill’s Research on Digital Subscriptions Empowers Newsrooms

    Here’s a neat trick that other newsrooms might want to steal. During Chicago’s recent election, the Tribune ran a quiz headlined, “Which Chicago mayoral candidate do you align most closely with?” The Tribune got candidates to answer a set of 14 questions, and then readers were invited to answer the same questions and learn which politician they were most in synch with. The feature served multiple purposes: educating readers on the candidates, helping readers focus their...

    Continue Reading

  • USC’s Crosstown Project Turns Big Data into Local News

    Gabriel Kahn says his data project, Crosstown, delivers “the kind of information that allows citizens to be the squeaky wheel.” Kahn, a professor at the University of Southern California’s Annenberg School of Journalism, and his team are developing Crosstown to analyze and publish data on “core quality-of-life issues” such as traffic, crime and air quality. The goal: to make large data sets useful on a local and even hyperlocal level. “Part of it comes from my...

    Continue Reading