The University of Adelaide
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Data for the Farewell and Herberg example of a two-phase experiment using a plaid design

posted on 2021-06-12, 06:32 authored by Chris BrienChris Brien
The experiment that Farewell and Herzberg (2003) describe is pain-rating experiment that is a subset of the experiment reported by Solomon et al. (1997). It is a two-phase experiment. The first phase is a self-assessment phase in which patients self-assess for pain while moving a painful shoulder joint. The second phase of this experiment is an evaluation phase in which occupational and physical therapy students (the raters) are evaluated for rating patients in a set of videos for pain. The measured response is the difference between a student rating and the patient's rating.

The R data file plaid.dat.rda contains the data.frame plaid.dat that has a revised version of the data for the Farewell and Herzberg example downloaded from The comma delimited text file plaid.dat.csv has the same information in this more commonly accepted format, but without the metadata associated with the data.frame<\CODE>.

The data.frame contains the factors Raters, Viewings, Trainings, Expressiveness, Patients, Occasions, and Motions and a column for the response variable Y. The two factors Viewings and Occasions are additional to those in the downloaded file and the remaining factors have been converted from integers or characters to factors and renamed to the names given above. The column Y is unchanged from the column in the original file.

To load the data in R use:

load("plaid.dat.rda") or

plaid.dat <- read.csv(file = "plaid.dat.csv").


Farewell, V. T.,& Herzberg, A. M. (2003). Plaid designs for the evaluation of training for medical practitioners. Journal of Applied Statistics, 30(9), 957-965.

Solomon, P. E., Prkachin, K. M. & Farewell, V. (1997). Enhancing sensitivity to facial expression of pain. Pain, 71(3), 279-284.