make.univ {multilevel}R Documentation

Convert data from multivariate to univariate form

Description

Longitudinal data is typically stored in multivariate or wide form. In multivariate form, each row contains data from one subject even when the subject provides data at multiple time periods (eg. OUTCOME1, OUTCOME2, OUTCOME3). In the case of repeated measures designs and growth modeling it is necessary to convert the data to univariate or stacked form where each row represents a single time indexed by a variable such as TIME and where each subject has multiple rows of data.

Usage

make.univ(x,dvs,tname="TIME", outname="MULTDV")

Arguments

x A dataframe in multivariate form.
dvs A subset dataframe of x containing the repeated measures columns. Note that dvs must be time-ordered from Time 1 to Time N for this function to work properly.
tname An optional name for the new time variable. Defaults to TIME.
outname An optional name for the outcome variable name. Defaults to MULTDV.

Value

Returns a new dataframe in univariate (i.e., stacked) form with a new variable named TIME representing the time intervals and a new variable named MULTDV representing the stacked multilple dependent variables. The TIME variable begins with 0.

Author(s)

Paul Bliese paul.bliese@us.army.mil

References

Bliese, P. D., & Ployhart, R. E. (2002). Growth modeling using random coefficient models: Model building, testing and illustrations. Organizational Research Methods, 5, 362-387.

Examples

data(univbct)  #a dataframe in univariate form for job satisfaction
TEMP<-univbct[3*1:495,c(22,1:17)]  #convert back to multivariate form

#Transform data to univariate form
TEMP2<-make.univ(x=TEMP,dvs=TEMP[,c(10,13,16)]) 

#Same as above, but renaming repeated variable
TEMP3<-make.univ(x=TEMP,dvs=TEMP[,c(10,13,16)],outname="JOBSAT")  

[Package multilevel version 2.3 Index]