# measurement: Levels of Measurement of Survey Items In codebooks: Management of Survey Data

## 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

 ```1 2 3 4 5 6 7 8``` ```## S4 method for signature 'item' measurement(x) ## S4 replacement method for signature 'item' measurement(x) <- value is.nominal(x) is.ordinal(x) is.interval(x) is.ratio(x) ```

## Arguments

 `x` an object, usually of class `"item"`. `value` a 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.

## References

Stevens, Stanley S. 1946. "On the theory of scales of measurement." Science 103: 677-680.

## See Also

`data.set`, `item`

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11``` ```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]] measurement(answer) <- "interval" as.data.frame(answer)[[1]] ```

codebooks documentation built on May 31, 2017, 3:35 a.m.