sample_random_prop: Sample a proportion of patients (or other observational...

In wjchulme/osutils: Useful Functions for OpenSAFELY

Sample a proportion of patients (or other observational units) based on patient IDs

Description

Sample a proportion of patients (or other observational units) based on patient IDs

Usage

sample_random_prop(id, proportion)

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
proportion	The proportion of patients (amongst all those who did not experience the event) to be sampled

Details

Result is TRUE with probability p and FALSE with probability 1-p. p is equal to
ceiling(length(id)*proportion)/length(id), which is equal to proportion when
length(id)*proportion is an integer, and slightly higher otherwise. Patients are selected in ascending order of patient ID until the sampling proportion is met.

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.