Calculate some stats about the waiting list — wl

A summary of all the key stats associated with a waiting list

Usage

wl_stats(waiting_list, target_wait = 4, start_date = NULL, end_date = NULL)

Arguments

waiting_list: data.frame. A df of referral dates and removals
target_wait: numeric. The required waiting time
start_date: date. The start date to calculate from
end_date: date. The end date to calculate to

Value

A data.frame of key waiting list summary statistics based on queueing theory:

mean_demand: Numeric. Mean number of additions to the waiting list per week.
mean_capacity: Numeric. Mean number of removals from the waiting list per week.
load: Numeric. Ratio between demand and capacity.
load_too_big: Logical. Whether the load is greater than or equal to 1, indicating whether the waiting list is unstable and expected to grow.
count_demand: Numeric. Total demand (i.e., number of referrals) over the full time period.
queue_size: Numeric. Number of patients on the waiting list at the end of the time period.
target_queue_size: Numeric. The recommended size of the waiting list to achieve approximately 98.2% of patients being treated within their target wait time. This is based on Little’s Law, assuming the system is in equilibrium, with the average waiting time set to one-quarter of the target_wait.
queue_too_big: Logical. Whether queue_size is more than twice the target_queue_size. A value of TRUE indicates the queue is at risk of missing its targets.
mean_wait: Numeric. Mean waiting time in weeks.
cv_arrival: Numeric. Coefficient of variation in the time between additions to the waiting list.
cv_removal: Numeric. Coefficient of variation in the time between removals from the waiting list.
target_capacity: Numeric. The weekly treatment capacity required to maintain the waiting list at its target equilibrium, assuming the target queue size has been reached.
relief_capacity: Numeric. The temporary weekly capacity required to reduce the waiting list to its target_queue_size within 26 weeks, assuming current demand remains steady. Calculated only if queue_too_big is TRUE; otherwise returns NA.
pressure: Numeric. A measure of pressure on the system, defined as 2 × mean_wait / target_wait. Values greater than 1 suggest the system is unlikely to meet its waiting time targets.

Examples


referrals <- c.Date("2024-01-01", "2024-01-04", "2024-01-10", "2024-01-16")
removals <- c.Date("2024-01-08", NA, NA, NA)
waiting_list <- data.frame("referral" = referrals, "removal" = removals)
waiting_list_stats <- wl_stats(waiting_list)