HIV | R Documentation |
Epidemiological capture-recapture data on HIV from four reporting centers in Rome, Italy.
HIV
15 by 5 numeric matrix, with the following columns:
c1
, c2
, c3
, c4
Capture histories from the four capture occasions
freq
Observed frequencies for each capture history
The capture histories were obtained by linking the records of the four reporting centers.
Each row of this data set represents an observed capture history followed by its frequency.
Abeni, D.A., Brancato, G. and Perucci, C. A. (1994) Capture-recapture to estimate the size of the population with human immunodeficiency virus type 1 infection. Epidemiology, 5, 410–414.
Baillargeon, S. and Rivest, L.P. (2007) Rcapture: Loglinear models for capture-recapture in R. Journal of Statistical Software, 19(5), doi: 10.18637/jss.v019.i05.
desc <- descriptive(HIV, dfreq=TRUE) desc # 1774 out of 1896 individuals (94%) appear on one list only. plot(desc) # The fi plot is linear showing that heterogeneity is not a problem. # Models with a time (or list) effect and possible pairwise dependencies # between lists will be considered. cp.m1 <- closedpCI.t(HIV, dfreq = TRUE, mX = ~ (c1+c2+c3+c4)^2, mname = "Mt double interaction") cp.m1 # The model fits well. Let's find out which interactions are important. summary(cp.m1$fit)$coefficients # Eliminating the non significant interactions stepwise shows that only # the [1,2] interaction is important. closedpCI.t(HIV, dfreq = TRUE, mX = ~ . + c1:c2, mname = "Mt interaction 1,2")
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