The use of historical control information in testing for a trend in Poisson means

A method is developed for the use of historical control information in testing for a trend with Poisson data. The resulting test statistic is a modification of a statistic proposed by Armitage (1955, Biometrics 11, 375-386) to test for a trend in frequencies. The contribution of the historical control data in the analysis depends upon the degree of heterogeneity of the historical counts.