In recent years, media franchises have grown in popularity. The most well-known example is the Marvel universe, including films such as The Avengers and series such as Agents of S.H.I.E.L.D., but DC Comics has caught up with a slate of shows on CW, including Arrow and Supergirl. Older shows (generally crime procedurals) also belong to franchises, notably the long-running CSI and Law & Order series. A popular way of promoting new entries in the series universe is to have crossover episodes, where characters and storylines for two or more shows interact. One of the biggest crossovers to date happened recently, with all four DC shows involved in the same story over four nights. The linear ratings during these events often rise, but how is overall demand affected?
To investigate the effect of crossover episodes on demand for the participating shows, the average demand during four weeks before the event is compared to the average demand during and one week afterwards. The growth in demand is the percent difference between the demand before to the demand after the crossover event. These Demand Expressions™ are from the United States as all eight crossovers occur in this market.
In general, crossover events increase demand, at least during the week after the event. Excluding The Vampire Diaries/The Originals, which was the only crossover to decline, crossover events caused demand for the involved shows to grow by an average of 12%. The two-day event involving all three Chicago series on NBC grew the most, increasing by 21% to nearly 5 million Demand Expressions™.
The Brooklyn Nine-Nine/New Girl crossover in October 2016 had the smallest increase at only 2%. The only other single-digit increase belonged to Bones and Sleepy Hollow. Perhaps shows that are not explicitly related (i.e., do not belong to the same franchise or universe) benefit less from crossover events as fans are less likely to start watching an unrelated title. Overall, though, crossover episodes tend to generate more demand for both series.
With more interrelated titles being produced (with comics companies Marvel and DC leading the way), characters and storylines appearing across multiple shows will become more common. Happily for these studios, this cross-pollination tends to make all related titles more popular, and so expect to see even more crossover events in 2017.