Sample sizes for identifying the key types of container occupied by dengue-vector pupae: the use of entropy in analyses of compositional data.
A method has been developed for estimating the sample sizes needed to identify categories that comprise a large proportion of a compositional data-set. The method is to be used in the design of surveys of mosquito pupae, for identifying the key container types from which the majority of adult dengue vectors emerge. Although a finite-population correction was devised for estimating the mean of a negative binomial distribution, other complications of parametric approaches make them unlikely to yield methods simple enough to be practically applicable. The Shannon-Wiener index was therefore investigated as a more useful alternative, at the cost of theoretical generalizability, in an approach based on re-sampling methods in conjunction with the use of entropy. This index can be used to summarize the degree to which pupae are either concentrated in a few container types, or dispersed among many. An empirical relationship between the index and the repeatability of surveys of differing sample sizes was observed. A step-wise rule, based on the entropy of the cumulative data, was devised for determining the sample size, in terms of the number of houses positive for pupae, at which a pupal survey might reasonably be stopped.
Alexander
N
N
Infectious Disease Epidemiology Unit, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K. neal.alexander@lshtm.ac.uk
Lenhart
A E
AE
Romero-Vivas
C M E
CM
Barbazan
P
P
Morrison
A C
AC
Barrera
R
R
Arredondo-Jiménez
J I
JI
Focks
D A
DA
D000330:Aedes; D000465:Algorithms; D000818:Animals; D003715:Dengue / Q000635:transmission; D019277:Entropy; D006794:Household Articles; D006801:Humans; D007303:Insect Vectors; D011159:Population Surveillance / Q000379:methods; D011679:Pupa; D015203:Reproducibility of Results; D018401:Sample Size; D014881:Water Supply