R/simIReff.R

In simIReff: Stochastic Simulation for Information Retrieval Evaluation: Effectiveness Scores

#' \code{simIReff}: Stochastic Simulation for Information Retrieval Evaluation: Effectiveness Scores
#'
#' Provides tools for the stochastic simulation of effectiveness scores to mitigate data-related
#' limitations of Information Retrieval evaluation research. These tools include:
#' \itemize{
#'   \item Fitting of continuous and discrete distributions to model system effectiveness.
#'   \item Plotting of effectiveness distributions.
#'   \item Selection of distributions best fitting to given data.
#'   \item Transformation of distributions towards a prespecified expected value.
#'   \item Proxy to fitting of copula models based on these distributions.
#'   \item Simulation of new evaluation data from these distributions and copula models.
#' }
#'
#' @references J. Urbano and T. Nagler. (2018). Stochastic Simulation of Test Collections:
#'   Evaluation Scores. ACM SIGIR.
#' @examples
#' \donttest{
#' ## Fit a marginal AP distribution and simulate new data
#' x <- web2010ap[,10] # sample AP scores of a system
#' e <- effContFitAndSelect(x, method = "BIC") # fit and select based on log-likelihood
#' plot(e) # plot pdf, cdf and quantile function
#' e$mean # expected value
#' y <- reff(50, e) # simulation of 50 new topics
#'
#' ## Transform the distribution to have a pre-specified expected value
#' e2 <- effTransform(e, mean = .14) # transform for expected value of .14
#' plot(e2)
#' e2$mean # check the result
#'
#' ## Build a copula model of two systems
#' d <- web2010ap[,2:3] # sample AP scores
#' e1 <- effCont_norm(d[,1]) # force the first margin to follow a truncated gaussian
#' e2 <- effCont_bks(d[,2]) # force the second margin to follow a beta kernel-smoothed
#' cop <- effcopFit(d, list(e1, e2)) # copula
#' y <- reffcop(1000, cop) # simulation of 1000 new topics
#' c(e1$mean, e2$mean) # expected means
#' colMeans(y) # observed means
#'
#' ## Modify the model to both systems have the same distribution
#' cop2 <- cop # copy the model
#' cop2$margins[[2]] <- e1 # modify 2nd margin
#' y <- reffcop(1000, cop2) # simulation of 1000 new topics
#' colMeans(y) # observed means
#'
#' ## Automatically build a gaussian copula to many systems
#' d <- web2010p20[,1:20] # sample P@20 data from 20 systems
#' effs <- effDiscFitAndSelect(d, support("p20")) # fit and select margins
#' cop <- effcopFit(d, effs, family_set = "gaussian") # fit copula
#' y <- reffcop(1000, cop) # simulate new 1000 topics
#'
#' # compare observed vs. expected mean
#' E <- sapply(effs, function(e) e$mean)
#' E.hat <- colMeans(y)
#' plot(E, E.hat)
#' abline(0:1)
#'
#' # compare observed vs. expected variance
#' Var <- sapply(effs, function(e) e$var)
#' Var.hat <- apply(y, 2, var)
#' plot(Var, Var.hat)
#' abline(0:1)
#'
#' # compare distributions
#' o <- order(colMeans(d))
#' boxplot(d[,o])
#' points(colMeans(d)[o], col = "red", pch = 4) # plot means
#' boxplot(y[,o])
#' points(colMeans(y)[o], col = "red", pch = 4) # plot means
#' }
"_PACKAGE"