The goal of RCMsize is to calculate the sample size required for
studies where the main outcome measure is the seroconversion rate
(SCR). It provides tools to compute the probability of an
individual being seropositive, given specific parameters such as the
seroconversion rate (SCR) , the seroreversion rate
(SRR), and the individual’s age, using a reversible
catalytic model. Additionally, the package allows for the calculation of
seroprevalence (SP) and its corresponding confidence
interval, as well as the confidence interval for the seroconversion rate
(SCR).
To install the RCMsize package from GitHub use one of the following commands:
devtools::install_github(“https://github.com/marciagraca/RCMsize”)
remotes::install_github(“https://github.com/marciagraca/RCMsize”)
After the installation is complete, you can load the RCMsize package into your R session by running:
library(RCMsize)
In this example we calculate the required sample size so that the
relative width of the confidence interval for the seroconversion rate
(SCR) is equal to a specified value (RL). The
function calculates the necessary sample size by iteratively adjusting
the sample size until the confidence interval for SCR meets the desired
width criteria. This calculation is based on the seroprevalence,
confidence intervals for seroprevalence, and the seroconversion
rate.
SCR: The seroconversion rate.RL: The desired relative width for the confidence
interval width for the seroconversion rate.SRR: The seroreversion rate.ages: A vector representing the distribution of ages in
the population.A_max: The maximum age in the population.limits: The lower and upper limits for the
SCR.max_iter: The maximum number of iterations for
adjusting the sample size (default is 10000).conf.level: The confidence level for the confidence
interval (default is 0.95).method: The method for calculating the confidence
interval for seroprevalence, default is "asymptotic".A_max <- 80
age_distribution <- rep(1 / A_max, A_max)
sample_s(0.03, 1, 0.01, age_distribution, A_max, limits = c(0, 1))For more information on reversible catalytic models, please refer to the following article.