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SURVEILLANCE OF RARE EVENTS. ON EVALUATION OF THE SETS METHOD

By Hrafnhildur Arnkelsdóttir

Abstract

Continual surveillance aiming to detect an increased frequency of some rare event is of interest in several different situations in quality control, medicine, economics and other fields. Examples are continual surveillance of defect articles in a production process or surveillance of a business cycle. Surveillance of rare health events in general and especially surveillance of congenital malformations has been a field of unabating interest during the last decades. Since the Thalidomide episode in the early 60's, several registries of congenital malformations are in operation all over the world. The basic idea is that if a 'catastrophe' occurs an alarm should be signalled as soon as possible after the occurrence. A method developed for this situation is the Sets method that focuses on the intervals between events under surveillance, e.g. intervals between successive births of malformed babies. If a previously defined number of such intervals are 'short' an alarm is triggered. The traditional evaluation measure used when discussing the Sets method is the ARL (Average Run Length). Here, evaluation measures such as the probability of a false alarm, the probability of a successful detection and the predictive value of an alarm are derived and discussed for the Sets method. The information provided by these measures is important for the implementation and use of a system of surveillance in practice

Topics: surveillance, rare health events, congenital malformations, the Sets method, probability of a false alarm, probability of a successful detection, predictive value
Publisher: University of Gothenburg
Year: 1995
OAI identifier: oai:gupea.ub.gu.se:2077/24600
Journal:

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Citations

  1. (1978). 9 If XU) is assumed to be exponentially distributed, d. Chen
  2. (1990). A Monitoring System to Detect Increased Rates of Cancer Incidence.
  3. (1989). A Surveillance System Based on a Short Memory Scheme. Statistics in Medicine. doi
  4. (1986). and Kenett and Pollak
  5. confirms these results and demonstrates the characteristic look of the plot of the false alarm probability at each decision point a· (s) vs. the decision point s. Note especially the distinct peek at s=n. a'
  6. (1990). Det svenska Missbildningsregistrets verksamhet.
  7. Detection of successive changes. doi
  8. (1993). discusses the CUSETS method, a method partly based on the same idea as the Sets method. Other methods described in the context of surveillance of congenital malformations are for example Healy's weighted regression and sequential analysis by Barbujani
  9. (1950). If s>2n, using the relation in Section 4.1, we have a*Cs) = p{ a ACs)IDCs)} = p{ A( S)!D(S)}[ 1-Ip {. A(j)!D( s)} ] = a'(n+l>[l- ~la'(j)] co According to Feller
  10. If s~n the cumulative false alarm probability is as = p{AsID(s)} = p{aAsID(s)} = ± p{ a A(j)ID(j) } j=n using the fact that a A(j')na A(j") = 0, j' =f. j". GO We know from Feller
  11. (1991). is a non increasing sequence of sets, d. Frisen and deMan~
  12. (1987). Monitoring Intervals between Rare Events: A Cumulative Score Procedure Compared with Rina Chen's Sets Technique.
  13. (1989). On Detection of a Change in the Dynamics of Rare Health Events. doi
  14. (1994). On performance of methods for statistical surveillance.
  15. (1989). Population Surveillance of Congenital Malformations. Possibilities and Limitations. Acta Paediatr Scand. doi
  16. (1995). Statistical methods for postmarketing surveillance.
  17. (1991). Statistical methods for surveillance of congenital malformations: when do the data indicate a true shift in the risk that an infant is affected by some type of malformation?
  18. (1988). Surveillance of congenital malformations and birth defects.
  19. (1988). Testing for a Change-point in Registry Data with an Example on Hypospadias. Statistics in Medicine. doi
  20. (1978). THE SETS METHOD The Sets method, introduced by Chen
  21. (1992). Using the Cuscore technique in the surveillance of rare health events. doi

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