Recruitment, data collection, participation rate, and representativeness of the international cross-sectional PRICOV-19 study across 38 countries

Table 2 Estimates of the number of GP practices invited to participate per invitation strategy

Invitation strategy	Reported number of GP practices invited to participate
Published invitation only (N = 2)
Participants invited, min – max	1669 – 2580
Participants invited, median (IQR)	2125 (1897, 2352)
Direct contact of all GP practices only (N = 12)
Participants invited, min – max	130 – 30,000
Participants invited, median (IQR)	950 (560, 1569)
Contact of a sample of GP practices only (N = 10)
Participants invited, min – max	40 – 873
Participants invited, median (IQR)	331 (104, 575)
Other invitation strategy used only (N = 3)
Participants invited, min – max	293 – 1270
Participants invited, median (IQR)	746 (520, 1008)
Countries that used multiple invitation strategies^a (N = 11)
Participants invited, min – max	40 – 11,200
Participants invited, median (IQR)	425 (213, 1072)

IQR Interquartile range
^a Lithuania and Romania used a sample of GP practices combined with another strategy; Luxembourg and Norway used a published invitation combined with direct contact of all GP practices; Bosnia and Herzegovina, North Macedonia, and Serbia used a published invitation combined with a sample of GP practices and with direct contact of all GP practices; Belgium and Israel used a published invitation combined with a sample of GP practices and with another strategy; and Portugal and Ukraine used a sample of GP practices combined with direct contact with all GP practices

ISSN: 2731-4553