calc_target_queue_size: Target Queue Size

In NHSRwaitinglist: Waiting List Metrics Using Queuing Theory

Target Queue Size

Description

Uses Little's Law to calculate the target queue size to achieve a target waiting time as a function of observed demand, target wait and a variability factor used in the target mean waiting time calculation.

Target Queue Size = Demand * Target Wait / 4.

The average wait should sit somewhere between target_wait/factor=6 < Average Waiting Time < target_wait/factor=4 The factor defaults to 4.

Only applicable when Capacity > Demand.

Usage

calc_target_queue_size(demand, target_wait, factor = 4)

Arguments

demand	Numeric value of rate of demand in same units as target wait e.g. if target wait is weeks, then demand in units of patients/week.
target_wait	Numeric value of number of weeks that has been set as the target within which the patient should be seen.
factor	Numeric factor used in average wait calculation to get a quarter of the target use factor=4 to get one sixth of the target use factor = 6 etc. Defaults to 4.

Value

Numeric target queue length.

Examples

# If demand is 30 patients per week and the target wait is 52 weeks, then the
# Target queue size = 30 * 52/4 = 390 patients.

calc_target_queue_size(30, 52, 4)

NHSRwaitinglist documentation built on April 3, 2025, 10:28 p.m.