R: Clarity of inhaler instructions

inhaler {brms} | R Documentation

## Clarity of inhaler instructions

### Description

Ezzet and Whitehead (1991) analyze data from a two-treatment, two-period crossover trial to compare 2 inhalation devices for delivering the drug salbutamol in 286 asthma patients. Patients were asked to rate the clarity of leaflet instructions accompanying each device, using a 4-point ordinal scale.

### Usage

    inhaler

### Format

A data frame of 572 observations containing information on the following 5 variables.

subject

  The subject number

rating

  The rating of the inhaler instructions on a scale ranging from 1 to 4

treat

  A contrast to indicate which of the two inhaler devices was used

period

  A contrast to indicate the time of administration

carry

  A contrast to indicate possible carry over effects

### Source

Ezzet, F., & Whitehead, J. (1991). A random effects model for ordinal responses from a crossover trial. Statistics in Medicine, 10(6), 901-907.

### Examples

    ## Not run:
    ## ordinal regression with family "sratio"
    fit1 <- brm(rating ~ treat + period + carry,
                data = inhaler, family = sratio(),
                prior = set_prior("normal(0,5)"))
    summary(fit1)
    plot(fit1)

    ## ordinal regression with family "cumulative"
    ## and random intercept over subjects
    fit2 <- brm(rating ~ treat + period + carry + (1|subject),
                  data = inhaler, family = cumulative(),
                  prior = set_prior("normal(0,5)"))
    summary(fit2)
    plot(fit2)

    ## End(Not run)

[Package brms version 2.16.3 Index]