Bernstein, S.L, Rennie W.P., and Alagappan K.

"Impact of Yankee Stadium Bat Day on blunt trauma in northern New York City"

Annals of Emergency Medicine
23 no.3 (1994): 555-559.
Study objective:
To determine the incidence of blunt trauma in northern New York City before and after the distribution of 25,000 baseball bats at Yankee Stadium.

Design:
Prospective multicenter study, including ten days before and ten days after Bat Day (June 3, 1990).

Setting:
Ten emergency departments in the Bronx and northern Manhattan.

Type of participant:
All patients presenting to the ED with baseball bat injuries.

Interventions:
Each hospital collected the following data for each subject: consciousness, results of computed tomography scan of the brain (if performed), history source, and disposition of the patient. Average daily atmospheric temperature was recorded for each day of the study.

Measurements and main results:
Seventy-seven patients sustained bat injuries, 38 (49%) before and 36 (47%) after Bat Day. There were no significant differences between the two groups with respect to age, sex, time of injury, number and distribution of fractures and lacerations, incidence of loss of consciousness, source of history, or disposition. There was a positive association between the number of cases on a given day and the average temperature that day (r = .5; P lt .01).

Conclusion:
The distribution of 25,000 wooden baseball bats to attendees at Yankee Stadium did not increase the incidence of bat-related trauma in the Bronx and northern Manhattan. There was a positive correlation between daily temperature and the incidence of bat injury. The informal but common impressions of emergency clinicians about the cause-and-effect relationship between Bat Day and bat trauma were unfounded.