norcag {mixor} | R Documentation |
Each subject provided ordinal responses on three items concerning their opinion on early teens (age 14-16) having sex before marriage (Item1), a man and a woman having sex before marriage (Item2), and a married person having sex with someone other than their spouse (Item3). Data are provided as frequencies by response pattern.
data(norcag)
A data frame with 105 observations on the following 6 variables.
ID
a numeric vector indicating unique patient identifier
SexItems
ordinal item response coded as 1 = always wrong; 2 = almost always wrong; 3 = wrong only sometimes; 4 = not wrong
int
a numeric vector of ones; used in the stand-alone MIXOR program to indicate the intercept
Item2vs1
attitude towards premarital vs teenage sex
Item3vs1
attitude towards extramarital vs teenage sex
freq
frequency weight of the pattern
Agresti A. and Lang J.B. (1993) A proportional odds model with subject-specific effects for repeated ordered categorical responses, Biometrika 80, 527-534.
Hedeker D. and Mermelstein R.J. (1998) A multilevel thresholds of change model for analysis of stages of change data, Multivariate Behavioral Research 33, 427-455.
library("mixor") data("norcag") # random intercepts model assuming proportional odds for differences in item responses Fitted.norcag<-mixor(SexItems~Item2vs1+Item3vs1, data=norcag, id=ID, weights=freq, link="logit", nAGQ=20) summary(Fitted.norcag) # random intercepts model assuming non-proportional odds for differences in item responses Fitted.norcag.np<-mixor(SexItems~Item2vs1+Item3vs1, data=norcag, id=ID, weights=freq, link="logit", nAGQ=10, KG=2) summary(Fitted.norcag.np) # SCALING model Fitted.norcag.scale<-mixor(SexItems~Item2vs1+Item3vs1, data=norcag, id=ID, weights=freq, link="logit", nAGQ=10, KS=2) summary(Fitted.norcag.scale)