Methods Inf Med 1991; 30(03): 206-209
DOI: 10.1055/s-0038-1634838
Data Analysis
Schattauer GmbH

Poisson Approximation to a Negative Binomial Process in the Surveillance of Rare Health Events

G. Gallus
1   Institute of Biometry and Medical Statistics, University of Milan, Milan, Italy
,
G. Radaelli
1   Institute of Biometry and Medical Statistics, University of Milan, Milan, Italy
,
M. Marchi
2   Institute of Clinical Physiology of C.N.R., Pisa, Italy
› Author Affiliations
Further Information

Publication History

Publication Date:
08 February 2018 (online)

Abstract

The Poisson approximation to a negative binomial process is evaluated regarding the surveillance of rare health events in the framework of the “Sets” scheme. This scheme defines an alarm in terms of “distance” between consecutive events of interest. The system’s parameters are determined by minimizing the expected delay for an alarm when a given increase in the event rate has occurred, subject to a restriction on the rate of false alarms. It is shown that the main consequence of the Poisson approximation lies in an increase of the false alarm probability with respect to the assigned one, whilst influence on the expected delay for a true alarm is lower. It is, however, found that over a large range of practical instances, the Poisson assumption provides a reasonable description of the negative binomial process.

 
  • REFERENCES

  • 1 Bjerkedal T, Bakketeig LS. Surveillance of congenital malformations and other conditions of the newborn. Int J Epidemiol 1975; 04: 31-6.
  • 2 Hill GB, Spiecer CC, Weatherall JAC. The computer surveillance of congenital malformations. Br Med Bull 1968; 24: 215-8.
  • 3 Kallen B, Windberg J. A Swedish register of congenital malformations. Pediatrics 1968; 04: 765-76.
  • 4 Klemetti A, Saxen L. The Finnish Register of Congenital Malformations, Organization and Six Years of Experience. Helsinki: Health Service Research of the National Board of Health in Finland; 1970. no 9.
  • 5 Weatherall JAC, Haskey JC. Surveillance of malformations. Br Med Bull 1976; 32: 39-44.
  • 6 Page ES. Continuous inspection schemes. Biometrika 1954; 41: 100-15.
  • 7 Chen R. A surveillance system for congenital malformations. J Am Stat Ass 1978; 73: 323-7.
  • 8 Barbujani G, Calzolari E. Comparison of two statistical techniques for the surveillance of birth defects through a Monte Carlo simulation. Stat Med 1984; 03: 239-47.
  • 9 Gallus G, Mandelli C, Marchi M, Radaelli G. On surveillance methods for congenital malformations. Stat Med 1986; 05: 565-71.
  • 10 Cox R, Isham V. Point Processes. London: Chapman and Hall; 1980
  • 11 Kennet R, Pollak M. Detection of a shift in the probability of a rare event. J Am Stat Ass 1983; 78: 389-95.