sample_random_n: Sample n patients (or other observational units) based on...

In wjchulme/osutils: Useful Functions for OpenSAFELY

Sample n patients (or other observational units) based on patient IDs.

Description

Sample n patients (or other observational units) based on patient IDs.

Usage

sample_random_n(id, n)

Arguments

id	An integer patient identifier with the following properties: consistent between cohort extracts unique completely randomly assigned (no correlation with practice ID, age, registration date, etc etc) which should be true as it based on hash of true IDs strictly greater than zero
n	The number of patients (amongst all those who did not experience the event) to be sampled

Details

Result is TRUE with probability max(1,n/length(id)) and FALSE with probability min(0, 1 - n/length(id)). Patients are selected in ascending order of patient ID until the sampling number is met. Warns (does not fail) if n is greater than length(id).

Value

A logical vector indicating whether the patient has been sampled or not

wjchulme/osutils documentation built on Dec. 20, 2024, 9:56 a.m.