From 400f048c89ab06cc055a8108c38ca040316f313e Mon Sep 17 00:00:00 2001 From: Daniel Date: Sun, 10 Sep 2023 20:33:24 +0200 Subject: [PATCH] Minor bug: Default method in item_intercor() is 'pearson', not 'spearman' (#610) --- R/item_intercor.R | 29 ++++++++++++++--------------- man/item_intercor.Rd | 29 ++++++++++++++--------------- 2 files changed, 28 insertions(+), 30 deletions(-) diff --git a/R/item_intercor.R b/R/item_intercor.R index 41b29b920..56aae1d77 100644 --- a/R/item_intercor.R +++ b/R/item_intercor.R @@ -7,25 +7,24 @@ #' @param x A matrix as returned by the `cor()`-function, #' or a data frame with items (e.g. from a test or questionnaire). #' @param method Correlation computation method. May be one of -#' `"spearman"` (default), `"pearson"` or `"kendall"`. +#' `"pearson"` (default), `"spearman"` or `"kendall"`. #' You may use initial letter only. #' #' @return The mean inter-item-correlation value for `x`. #' -#' @details This function calculates a mean inter-item-correlation, i.e. -#' a correlation matrix of `x` will be computed (unless -#' `x` is already a matrix as returned by the `cor()`-function) -#' and the mean of the sum of all item's correlation values is returned. -#' Requires either a data frame or a computed `cor()`-object. -#' \cr \cr -#' \dQuote{Ideally, the average inter-item correlation for a set of -#' items should be between .20 and .40, suggesting that while the -#' items are reasonably homogeneous, they do contain sufficiently -#' unique variance so as to not be isomorphic with each other. -#' When values are lower than .20, then the items may not be -#' representative of the same content domain. If values are higher than -#' .40, the items may be only capturing a small bandwidth of the construct.} -#' \cite{(Piedmont 2014)} +#' @details This function calculates a mean inter-item-correlation, i.e. a +#' correlation matrix of `x` will be computed (unless `x` is already a matrix +#' as returned by the `cor()` function) and the mean of the sum of all items' +#' correlation values is returned. Requires either a data frame or a computed +#' `cor()` object. +#' +#' "Ideally, the average inter-item correlation for a set of items should be +#' between 0.20 and 0.40, suggesting that while the items are reasonably +#' homogeneous, they do contain sufficiently unique variance so as to not be +#' isomorphic with each other. When values are lower than 0.20, then the items +#' may not be representative of the same content domain. If values are higher +#' than 0.40, the items may be only capturing a small bandwidth of the +#' construct." _(Piedmont 2014)_ #' #' @references #' Piedmont RL. 2014. Inter-item Correlations. In: Michalos AC (eds) diff --git a/man/item_intercor.Rd b/man/item_intercor.Rd index 923c8a3f0..b59f8b8c5 100644 --- a/man/item_intercor.Rd +++ b/man/item_intercor.Rd @@ -11,7 +11,7 @@ item_intercor(x, method = c("pearson", "spearman", "kendall")) or a data frame with items (e.g. from a test or questionnaire).} \item{method}{Correlation computation method. May be one of -\code{"spearman"} (default), \code{"pearson"} or \code{"kendall"}. +\code{"pearson"} (default), \code{"spearman"} or \code{"kendall"}. You may use initial letter only.} } \value{ @@ -22,20 +22,19 @@ Compute various measures of internal consistencies for tests or item-scales of questionnaires. } \details{ -This function calculates a mean inter-item-correlation, i.e. -a correlation matrix of \code{x} will be computed (unless -\code{x} is already a matrix as returned by the \code{cor()}-function) -and the mean of the sum of all item's correlation values is returned. -Requires either a data frame or a computed \code{cor()}-object. -\cr \cr -\dQuote{Ideally, the average inter-item correlation for a set of -items should be between .20 and .40, suggesting that while the -items are reasonably homogeneous, they do contain sufficiently -unique variance so as to not be isomorphic with each other. -When values are lower than .20, then the items may not be -representative of the same content domain. If values are higher than -.40, the items may be only capturing a small bandwidth of the construct.} -\cite{(Piedmont 2014)} +This function calculates a mean inter-item-correlation, i.e. a +correlation matrix of \code{x} will be computed (unless \code{x} is already a matrix +as returned by the \code{cor()} function) and the mean of the sum of all items' +correlation values is returned. Requires either a data frame or a computed +\code{cor()} object. + +"Ideally, the average inter-item correlation for a set of items should be +between 0.20 and 0.40, suggesting that while the items are reasonably +homogeneous, they do contain sufficiently unique variance so as to not be +isomorphic with each other. When values are lower than 0.20, then the items +may not be representative of the same content domain. If values are higher +than 0.40, the items may be only capturing a small bandwidth of the +construct." \emph{(Piedmont 2014)} } \examples{ data(mtcars)