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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_fulllist:summary statistics describing the site, cluster assignments, and randomization.
geom_corelist:summary statistics describing the core area
trialdata frame:rows correspond to geolocated points, as follows:
xnumeric vector: x-coordinates of locations
ynumeric vector: y-coordinates of locations
clusterfactor: assignments to cluster of each location
armfactor: assignments to "control" or "intervention" for each location
nearestDiscordnumeric vector: signed Euclidean distance to nearest discordant location (km)
bufferlogical: 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)