Table 1. Algorithm sample from general practice.

Criteria	GP visits	Unique patient count
All data supplied	16,305,096	744,477
Those with a linked ED visit	37,789	21,376
Those with a linked ED visit within 1 year	26,691	12,448
Those with a linked ED visit within 1 year and no injury	20,213	10,610
Those with a linked ED visit within 1 year, no injury, with adequate data fields	17,067	8,479
Those without a linked ED visit used for the non-ED sample	150,000	144,490
Those without a linked ED visit used for the non-ED sample with adequate data fields	29,892	29,185

Abbreviations: ED, emergency department; GP, general practice.