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replace from "probability" to "proportion" in superspreading episode #165

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@avallecam

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@avallecam

On episode "account superspreading" (specifically in this section) we interpret proportion_cluster_size as:

estimate the probability of having a cluster of secondary infections caused by a primary case identified by backward tracing of size $X$ or larger (Endo et al., 2020)

However, for homogeneity with package documentation (manual, vignette), we should interpret it as:

estimate the proportion of new cases originating from a transmission cluster of at least $X$ cases (Knight et al., 2020). This estimate can give answer to a question like: how many cases are associated with large clusters? which is useful to assess backward contact training efforts.

Current template to update interpretations in working branch:

# Larger clusters are likely to be detected
# through backward tracing in the presence of overdispersion

set.seed(33)

# proportion-cluster size ------------------------------------------------

superspreading::proportion_cluster_size(
  R = 0.8, k = 0.1, cluster_size = 5
)
#>     R   k prop_5
#> 1 0.8 0.1  66.2%
# The proportion of new cases originating from 
# a cluster of at least 5 secondary cases from a primary case
# is 66%

# The proportion of all transmission event that were part of 
# secondary case clusters (i.e., from the same primary case)
# of at least 5 cases
# is 66%


# compare ----------------------------------------------------------------

superspreading::proportion_cluster_size(
  R = 0.9, k = 0.02, cluster_size = c(1, 2, 5, 10, 20)
)
#>     R    k prop_1 prop_2 prop_5 prop_10 prop_20
#> 1 0.9 0.02   100%  98.1%  92.1%   82.9%   66.6%
superspreading::proportion_cluster_size(
  R = 0.9, k = 0.1, cluster_size = c(1, 2, 5, 10, 20)
)
#>     R   k prop_1 prop_2 prop_5 prop_10 prop_20
#> 1 0.9 0.1   100%  91.9%  70.1%   43.4%   14.9%
superspreading::proportion_cluster_size(
  R = 0.9, k = 0.4, cluster_size = c(1, 2, 5, 10, 20)
)
#>     R   k prop_1 prop_2 prop_5 prop_10 prop_20
#> 1 0.9 0.4   100%  80.9%  34.6%   7.11%  0.146%

# the probability of (finding) new cases originating from
# a cluster of at least 5, 10, 20 secondary cases from a primary case
# increases when there is more overtransmission (lower k value)


# proportion-transmission ------------------------------------------------

superspreading::proportion_transmission(
  R = 0.8, k = 0.1, percent_transmission = 0.8
)
#>     R   k prop_80
#> 1 0.8 0.1   8.47%
# The proportion of cases responsible of 80% of transmission
# is 8.47%


# compare ----------------------------------------------------------------

superspreading::proportion_transmission(
  R = 0.9, k = 0.02, percent_transmission = 0.8
)
#>     R    k prop_80
#> 1 0.9 0.02   2.13%
superspreading::proportion_transmission(
  R = 0.9, k = 0.1, percent_transmission = 0.8
)
#>     R   k prop_80
#> 1 0.9 0.1   8.62%
superspreading::proportion_transmission(
  R = 0.9, k = 0.4, percent_transmission = 0.8
)
#>     R   k prop_80
#> 1 0.9 0.4   19.9%
# The proportion of cases responsible of 80% of transmission
# decreases (more concentrated in a lower proportion of cases)
# when there is more overtransmission (lower k value)

Created on 2025-04-01 with reprex v2.1.1

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