specify_buffer {CRTspat}R Documentation

Specification of buffer zone in a cluster randomized trial


specify_buffer specifies a buffer zone in a cluster randomized trial (CRT) by flagging those locations that are within a defined distance of those in the opposite arm.


specify_buffer(trial, buffer_width = 0)



an object of class "CRTsp" or a data frame containing locations in (x,y) coordinates, cluster assignments (factor cluster), and arm assignments (factor arm).


minimum distance between locations in opposing arms for them to qualify to be included in the core area (km)


A list of class "CRTsp" containing the following components:

geom_full list: summary statistics describing the site, cluster assignments, and randomization.
geom_core list: summary statistics describing the core area
trial data frame: rows correspond to geolocated points, as follows:
x numeric vector: x-coordinates of locations
y numeric vector: y-coordinates of locations
cluster factor: assignments to cluster of each location
arm factor: assignments to "control" or "intervention" for each location
nearestDiscord numeric vector: signed Euclidean distance to nearest discordant location (km)
buffer logical: indicator of whether the point is within the buffer
... other objects included in the input "CRTsp" object or data frame


#Specify a buffer of 200m
exampletrial <- specify_buffer(trial = readdata('exampleCRT.txt'), buffer_width = 0.2)

[Package CRTspat version 1.2.0 Index]