Average daily population

The mean number of person-days served per day over a period: a STOCK, answering how many people are held at one time.

Usage

adp(days, t = 365)

Arguments

days

Person-days served during the period. A vector is summed, so one element per person is the usual input.

t

Length of the period in days. Default 365.

Value

A single number: person-days per day.

Details

This is Lakner's \(\bar{X}_{hc} = \sum X_i / t\) (1976, p.15). The denominator is TIME, which is what makes it a stock. Compare alos(), whose denominator is people.

References

Lakner, E. (1976) A Manual of Statistical Sampling Methods for Corrections Planners. University of Illinois at Urbana-Champaign.

See also

alos(), stock_flow(), adp_from_counts()

Examples

# Lakner's own worked example (p.15): 3,000 inmates served 13,500
# detention days in a year.
adp(13500)
#> [1] 36.9863

# per-person days give the same total
adp(c(10, 20, 30), t = 30)
#> [1] 2