scaleDiagnosis: scaleDiagnosis

In userfriendlyscience: Quantitative Analysis Made Accessible

Description

scaleDiagnosis provides a number of diagnostics for a scale (an aggregative measure consisting of several items).

Usage

scaleDiagnosis(dat=NULL, items=NULL, plotSize=180, sizeMultiplier = 1,
               axisLabels = "none", scaleReliability.ci=FALSE, conf.level=.95,
               powerHist=TRUE, ...) 

Arguments

dat	A dataframe containing the items in the scale. All variables in this dataframe will be used if items is NULL.
items	If not NULL, this should be a character vector with the names of the variables in the dataframe that represent items in the scale.
plotSize	Size of the final plot in millimeters.
sizeMultiplier	Allows more flexible control over the size of the plot elements
axisLabels	Passed to ggpairs function to set axisLabels.
scaleReliability.ci	TRUE or FALSE: whether to compute confidence intervals for Cronbach's Alpha and Omega (uses bootstrapping function in MBESS, takes a while).
conf.level	Confidence of confidence intervals for reliability estimates (if requested with scaleReliability.ci).
powerHist	Whether to use the default ggpairs histogram on the diagonal of the scattermatrix, or whether to use the powerHist version.
...	Additional arguments are passed on to powerHist.

Details

Function to generate an object with several useful statistics and a plot to assess how the elements (usually items) in a scale relate to each other, such as Cronbach's Alpha, omega, the Greatest Lower Bound, a factor analysis, and a correlation matrix.

Value

An object with the input and several output variables. Most notably:

scaleReliability	The results of scaleReliability.
pca	A Principal Components Analysis
fa	A Factor Analysis
describe	Decriptive statistics about the items
scatterMatrix	A scattermatrix with histograms on the diagonal and correlation coefficients in the upper right half.

Author(s)

Gjalt-Jorn Peters

Maintainer: Gjalt-Jorn Peters <[e-mail]>

Examples

### Note: the 'not run' is simply because running takes a lot of time,
###       but these examples are all safe to run!
## Not run: 
### This will prompt the user to select an SPSS file
scaleDiagnosis();

### Generate a datafile to use
exampleData <- data.frame(item1=rnorm(100));
exampleData$item2 <- exampleData$item1+rnorm(100);
exampleData$item3 <- exampleData$item1+rnorm(100);
exampleData$item4 <- exampleData$item2+rnorm(100);
exampleData$item5 <- exampleData$item2+rnorm(100);

### Use a selection of two variables
scaleDiagnosis(dat=exampleData, items=c('item2', 'item4'));

### Use all items
scaleDiagnosis(dat=exampleData);

## End(Not run)

userfriendlyscience documentation built on May 2, 2019, 1:09 p.m.