Popularity of Harry Potter Series and Related Books
MAT 259, 2022
Yifei Liu

Since the card RPG mobile game “Harry Potter: Magic Awaken” released in September 2021, and “Harry Potter 20th Anniversary: Return to Hogwarts” reunited the main cast members across all eight Harry Potter films to share their memorable moment in December 2021, which aroused my emotional memory of childhood, waiting for the owl to deliver my acceptance letter to Hogwarts on 11th birthday. Being the same age as the young cast members, I feel like I grew up with “Harry Potter”. It is so overwhelming to see them sitting together after two decades, so I watched the Harry Potter film cut again during the new year.

Taking this opportunity, I would like to explore whether Harry Potter (HP) Series is still popular. Whether the release of films may have a positive impact on the book popularity. As the eight films of HP series have been released for a long time and HP is known for its related products, whether the related books and films, like the Fantasy Beast series, have positive impacts on the popularity of the book series. In order to investigate the popular trend, I collected 12 books in total, including 7 HP Series books and the 5 most popular HP official related books that can be found in Seattle Public Library (table 1).

SELECT DATE_FORMAT(cout, '%Y-%m') AS years, title, COUNT(bibNumber) AS Counts, SUM(CASE WHEN itemType = 'jcbk' THEN 1 ELSE 0 END) AS juvbook, SUM(CASE WHEN itemType = 'acbk' THEN 1 ELSE 0 END) AS adultbook, SUM(CASE WHEN itemType = 'jccas' OR itemType = 'jccd' OR itemType = 'jccdrom' OR itemType = 'jcvhs' THEN 1 ELSE 0 END) AS juvmedia, SUM(CASE WHEN itemType = 'accd' OR itemType = 'acdvd' OR itemType = 'acvhs' OR itemType = 'dcillb' THEN 1 ELSE 0 END) AS adultmedia FROM spl_2016.outraw WHERE title LIKE '%Harry Potter%' AND title LIKE '%chamber%' GROUP BY DATE_FORMAT(cout, '%Y-%m') , title ORDER BY DATE_FORMAT(cout, '%Y-%m')

Preliminary sketches
Table 1. Year of HP series and related books were published and films were released.

Firstly, I looked up all the entries that with “Harry Potter” in titles. Based on the results, I added more filter requirements (itemType, detailed title) to the query, and calculated the monthly check-in and check-out number of books and media respectively according to item types to juvenile book (juvbook, item type = “jcbk”), adult book (adultbook, item type = “acbk”), juvenile media (juvmedia, item type = “jccas” OR “jccd” OR “jccdrom” OR “jcvhs”), and adult media (adultmedia, item type = “accd” OR “acdvd” OR “acvhs”) for 12 books. The query and screenshot of the first result are shown in Query and Figure 1, respectively.

Figure 1. Screenshot of the first 24 entries of monthly check-in book number of “Harry Potter and the Sorcerer's Stone”. The first row with the year 1970-01 was abandoned in further analysis.

As “Harry Potter and the Deathly Hallows” films are split into Part 1 and Part 2, the modified adult media query is listed in Figure 2.

Figure 2. Modified MySQL query of monthly check-in adult media number of “Harry Potter and the Deathly Hallows” film Part 1 and Part 2.

Final result
We used check-out numbers to indicate the popularity of a book. As the check-out dataset started in January 2006, after the book was published of HP-6 and film released of HP-4 (Figure 4). Although the impact of HP 1-3 films was unknown, we can still explore the last 4 films.

Besides the sudden decrease in 2020 due to COVID-19, the check-out number of HP 1-3 remained quite stable, with small peaks appearing in 2012, 2017, and 2019, which is the year after HP-7 Film and Fantastic Beast film was released. To compare the time that each book reaches the peak check-out number with the newly published books and released films, the year of the book was published and the film was released, the year of peak check-out number during 2006-2021, and the years between the peak number and decreasing till average number (years remain popular) within 16 years were calculated in Table 2.

Figure 3. Charts of check-out numbers of each book and film in a year.

Table 2. Comparison of HP 4-7 series and three related books published and films released to time with years of peak check-out number, as well as years remain popular.

We can see that before the popular trend of the previous book decrease to a normal level, the publication of the next book or the release of the next film will turn public attention to the new series. Every time there is a new release, the check-out number of the whole series will increase a little at that year, and the window period is never longer than 1 year. Even though the HP series ended, the new related Fantastic Beasts series promoted the check-out number of the whole series. That is, if only the good-quality HP-related film continues to be released, the popularity of the HP series will never end.

To further analyze the juvenile books and media, and adult books and media separately in detail, the check-out numbers for each month are shown in Figure 5. Compare to popular book series like Twilight series and Fifty Shades of Grey series, the peak monthly check-out number of newly published books (HP-7 and CChild) can exceed 200. So, the HP series is still popular nowadays.

Compared to books, media like CD and DVD are much more popular. The majority of the check-out numbers of the Fantastic Beasts series are contributed by the media. It is interesting to find that the release of HP-6 and HP-7 films didn’t have much positive impact on the check-out numbers of HP book series, but have a positive impact on the related book like Quid. Furthermore, the release of the Fantastic Beasts series has a huge positive impact on earlier book check-out numbers, like HP-1 and HP-2, but has just a little impact on the latter book check-out number, like HP-6 and HP-7. The possible reason may be the related films attract new HP fans and they borrowed the book series from the first one, while the old fans who have already read the whole series may choose to rewatch the films rather than reread the books.

In conclusions, HP series is still popular these days as if new related books and films keep popping up. The releases of HP films do not have much impact on the book alone, but affecting the related book positively. Besides, the related Fantasy Beast series promoted the popularity of the whole series a lot. As HP official are good at arousing the emotional memories of fans, I predict that the HP series can still be popular for several decades.

All work is developed within Mysql