measurement
memisc
0.99.20.1
Levels of Measurement of Survey Items¶
Description¶
The measurement level of a "item" object, which is one of
“nominal”, “ordinal”, “interval”, “ratio”, determines what happens to
it, if it or the data.set containing it is coerced into a
data.frame. If the level of measurement level is “nominal”, the it
will be converted into an (unordered) factor, if the level of
measurement is “ordinal”, the item will be converted into an ordered
vector. If the measurement is “interval” or “ratio”, the item will be
converted into a numerical vector.
Usage¶
## S4 method for signature 'item'
measurement(x)
## S4 method for signature 'item'
measurement(x) <- value
is.nominal(x)
is.ordinal(x)
is.interval(x)
is.ratio(x)
Arguments¶
xan object, usually of class
"item".valuea character string; either “nominal”, “ordinal”, “interval”, or “ratio”.
Value¶
measurement(x) returns a character string. is.nominal,
is.ordinal, is.interval, is.ratio return a logical value.
See also¶
data.set, item
Examples¶
answer <- sample(c(1,2,3,8,9),size=30,replace=TRUE)
labels(answer) <- c(Conservatives = 1,
Labour = 2,
"Liberal Democrats" = 3,
"Don't know" = 8,
"Answer refused" = 9
)
missing.values(answer) <- c(8,9)
as.data.frame(answer)[[1]]
[1] Conservatives <NA> Conservatives <NA>
[5] Conservatives <NA> <NA> Conservatives
[9] Labour Conservatives <NA> Liberal Democrats
[13] <NA> Liberal Democrats <NA> <NA>
[17] <NA> <NA> Labour <NA>
[21] Labour <NA> Labour Liberal Democrats
[25] Labour <NA> Labour <NA>
[29] Labour Labour
Levels: Conservatives Labour Liberal Democrats
measurement(answer) <- "interval"
as.data.frame(answer)[[1]]
[1] 1 NA 1 NA 1 NA NA 1 2 1 NA 3 NA 3 NA NA NA NA 2 NA 2 NA 2 3 2
[26] NA 2 NA 2 2
