Abstract
Background: The Poisson distribution is used to find the probability of an event occurring over an interval of time, distance, area, or volume.
Problem: It is a helpful statistical tool, especially when evaluating rare events, and is underused in nursing practice.
Approach: A single-group study design is used to demonstrate use of the Poisson distribution in determining whether a change in the number of discrete events is due to random variation or reflects a change in practice patterns and in determining the probability of seeing the number of observed events.
Outcomes: Steps demonstrate how one can easily use the Poisson distribution to answer common questions.
Conclusion: Use of the Poisson distribution can help nurses make better informed decisions about observed variations in care, especially when the data are not normally distributed, and can prevent undue concern when fluctuations in the number of events are associated with random fluctuations.