The fewer exhibits that visitors view during their visit, the shorter their stay at the museum is likely to be. So during special exhibitions, the average length of visits is likely to be lower.

If the plan was never enacted, the museum’s hours didn’t change during the period studied. Knowing the museum’s hours didn’t change doesn’t help explain why patrons tend to take longer trips to the museum when the museum isn’t featuring a special exhibition.

If people only go to a special exhibition for the sake of attending, they have no reason to stay at the museum after seeing the exhibition. Therefore, these attendees are likely to lower the average amount of time spent on museum trips when a museum has a special exhibition.

If all tickets to the special exhibition are issued for a 1-hour period, the average visit length during periods with special exhibitions won’t be able to exceed an hour. This restriction could lower average visit times during a special exhibition.

When people can’t browse, their visit length is largely predetermined. Therefore, many of the special exhibition viewers will have greatly restricted visit lengths, likely lowering the average visit length during periods when the museum has a special exhibition.