Description

Artificial data set of 5 items, 5 time points and 5 groups for LLRA.

Usage

Format

A data frame with 150 observations of 26 variables.

t1.I1

Answers to item 1 at time point 1

t1.I2

Answers to item 2 at time point 1

t1.I3

Answers to item 3 at time point 1

t1.I4

Answers to item 4 at time point 1

t1.I5

Answers to item 5 at time point 1

t2.I1

Answers to item 1 at time point 2

t2.I2

Answers to item 2 at time point 2

t2.I3

Answers to item 3 at time point 2

t2.I4

Answers to item 4 at time point 2

t2.I5

Answers to item 5 at time point 2

t3.I1

Answers to item 1 at time point 3

t3.I2

Answers to item 2 at time point 3

t3.I3

Answers to item 3 at time point 3

t3.I4

Answers to item 4 at time point 3

t3.I5

Answers to item 5 at time point 3

t4.I1

Answers to item 1 at time point 4

t4.I2

Answers to item 2 at time point 4

t4.I3

Answers to item 3 at time point 4

t4.I4

Answers to item 4 at time point 4

t4.I5

Answers to item 5 at time point 4

t5.I1

Answers to item 1 at time point 5

t5.I2

Answers to item 2 at time point 5

t5.I3

Answers to item 3 at time point 5

t5.I4

Answers to item 4 at time point 5

t5.I5

Answers to item 5 at time point 5

groups

The group membership

Details

This is a data set as described in Hatzinger and Rusch (2009). 5 items were measured at 5 time points (in columns). Each row corresponds to one person (P1 to P150). There are 4 treatment groups and a control group. Treatment group G5 has size 10 (the first ten subjects), treatment group G4 has size 20, treatment group G3 has size 30, treatment group G2 has size 40 and the control group CG has size 50 (the last 50 subjects). Item 1 is dichotomous, all others are polytomous. Item 2, 3, 4 and 5 have 3, 4, 5, 6 categories respectively.

References

Hatzinger, R. and Rusch, T. (2009) IRT models with relaxed assumptions in eRm: A manual-like instruction. Psychology Science Quarterly, 51, pp. 87–120.

Examples