The following graph shows the trend for three major motion pictures released this year: Return of the Sith, Batman Begins and War of the Worlds:
Star Wars opened on May 19th, Batman Begins opened on June 15th, which corresponds to the first
major peak. War of the Worlds opened on June 29th.
Through its first Sunday, Star Wars grossed $158, 449, 700; Batman Begins $72, 896, 986, and War of the Worlds $100, 561, 125. Normalizing by the Star Wars gross, these numbers become 1.0, 0.46,
0.63. If we take similarly normalized percentages of blog posts (1.30, 0.80, 1.15), we get 1.0, 0.62, 0.88. Although the trend chart matches the overall ordering of grosses, the relationships are not linear. This observation is mirrored in the trend for the box office receipts (as reported by the excellent BoxOfficeMojo):
However, what we really want to do is to be able to predict some aspect of the movies receipts from the pre-release online trends. In addition, we want to be able to qualify the type of trends. In this example, both Batman Begins and War of the Worlds show weekly dips and peaks - not so Star Wars which shows no valleys between weekends. This lack of valleys does not correspond to a similar pattern in the receipts (as reported by BoxOfficeMojo) and so indicates not the volume of people seeing the movie but the level of excitement around the movie - in other words, the post movie chatter is more prolonged than for the other two.