Description

The data is obtained from a trial in which chronically ill mental health patients were randomized across two treatments: placebo and an active drug. A questionnaire instrument was used to assess each patient's mental state at weeks 0, 1, 2, 4, 6 and 8 post-randomisation, a high recorded score implying a severe condition. Some of the 100 patients dropped out of the study for reasons that were thought to be related to their mental state, and therefore potentially informative; others dropped out for reasons unrelated to their mental state.

Usage

Format

A balanced data set with respect to the times at which observations recorded. The data consists of the following variables on each patient:

id

integer: patient identifier.

Y.t0

integer: mental state assessment in week 0. Coded NA if missing.

Y.t1

integer: mental state assessment in week 1. Coded NA if missing.

Y.t2

integer: mental state assessment in week 2. Coded NA if missing.

Y.t4

integer: mental state assessment in week 4. Coded NA if missing.

Y.t6

integer: mental state assessment in week 6. Coded NA if missing.

Y.t8

integer: mental state assessment in week 8. Coded NA if missing.

treat

integer: treatment allocation. Coded as 0 = placebo; 1 = active drug.

n.obs

integer: number of non-missing mental state assessments.

surv.time

numeric: imputed dropout time in weeks. Coded as surv.time = 8.002 for completers.

cens.ind

integer: censoring indicator. Coded as 0 = completer or non-informative dropout; 1 = potentially informative dropout.

Source

Peter J. Diggle (p.diggle@lancaster.ac.uk)

References

Henderson R, Diggle PJ, Dobson A. Joint modelling of longitudinal measurements and event time data. Biostatistics. 2000; 1(4): 465-480.

Diggle PJ, Farewell D, Henderson R. Longitudinal data with dropout: objectives, assumptions and a proposal (with Discussion). Applied Statistics. 2007; 56: 499-550.

See Also

heart.valve, liver, epileptic.