item.reverse | R Documentation |
This function reverse codes inverted items, i.e., items that are negatively worded.
item.reverse(x, min = NULL, max = NULL, keep = NULL, names = ".r",
as.na = NULL, table = FALSE, check = TRUE)
x |
a numeric vector for reverse coding an item, matrix or data frame for reverse coding more than one item. |
min |
an integer indicating the minimum of the item (i.e., lowest possible scale value). |
max |
an integer indicating the maximum of the item (i.e., highest possible scale value). |
keep |
a numeric vector indicating values not to be reverse coded. |
names |
a character string or character vector indicating the names
of the reverse coded item when specifying more than one variable.
By default, variables are named with the ending |
as.na |
a numeric vector indicating user-defined missing values, i.e. these
values are converted to |
table |
logical: if |
check |
logical: if |
If arguments min
and/or max
are not specified, empirical minimum
and/or maximum is computed from the data Note, however, that reverse coding
might fail if the lowest or highest possible scale value is not represented in
the data That is, it is always preferable to specify the arguments min
and max
.
Returns a numeric vector or data frame with the same length or same number of
rows as x
containing the reverse coded scale item(s).
Takuya Yanagida takuya.yanagida@univie.ac.at
Rasch, D., Kubinger, K. D., & Yanagida, T. (2011). Statistics in psychology - Using R and SPSS. New York: John Wiley & Sons.
item.alpha
, item.omega
, rec
,
item.scores
dat <- data.frame(item1 = c(1, 5, 3, 1, 4, 4, 1, 5),
item2 = c(1, 1.3, 1.7, 2, 2.7, 3.3, 4.7, 5),
item3 = c(4, 2, 4, 5, 1, 3, 5, -99))
# Reverse code item1
dat$item1r <- item.reverse(dat$item1, min = 1, max = 5)
# Reverse code item3 while keeping the value -99
dat$item3r <- item.reverse(dat$item3, min = 1, max = 5, keep = -99)
# Reverse code item3 while keeping the value -99 and check recoding
dat$item3r <- item.reverse(dat$item3, min = 1, max = 5, keep = -99, table = TRUE)
# Reverse code item1, item2, and item 3 and attach to 'dat'
dat <- cbind(dat,
item.reverse(dat[, c("item1", "item2", "item3")],
min = 1, max = 5, keep = -99))
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