Adjusted Outpatient Census Formula

Standard, benchmark, or fixed information: Average length of stay (ALOS) = 140 minutes

X = census
Z = adjusted census
Y = number of patients in emergency department (ED) > 6 hours
T = average length of stay in minutes of Y

The formula uses the referenced fixed and variable data to demonstrate increased volume represented:

Z = (T x Y - ALOS x Y) + X


The ALOS at Lewis-Gale Medical Center ED is 140 minutes. If 83 patients came to the ED in 24 hours and 10 stayed more than six hours at an average of 513 minutes, the following adjusted census formula is true:

Z = (TY - 140Y) + X
Z = (513 x 10) - (140 x 10) + 83
= 5,130 - 1,400 + 83
= 26.64 + 83 = 109.64
patients (adjusted census)

This information is used to calculate an adjusted man-hour per patient ratio (adjusted patient census is 109 patients instead of 83). More man-hours were needed to care for patients on this day than was budgeted for typical outpatient acuity, even though the overall census volume did not support the additional manpower. The most applicable time to use this formula is when patients are held in the ED or other outpatient setting for inpatient care due to bed saturation.

Source: Camilla L. Jones, RN, Director, Emergency and Transfer Services, Lewis-Gale Medical Center, Salem, VA. Formula taken from: Zimmermann PG. Nursing Management Secrets. Philadelphia: Hanley & Belfus Inc. Medical Publishers; Copyright 2002.