Many of your staff will not show up in an emergency, and those that are there may go home according to a survey conducted by the Center for Public Health Preparedness at the Johns Hopkins Bloomberg School of Public Health.

The survey found that 66 percent of public health workers felt they would put themselves at risk of infection if they were to report to work during a flu pandemic. Over 40 percent of public health employees surveyed said they are unlikely to report to work during a pandemic.

This level of staff fall-out is consistent with other types of disasters when responsibilities at home -- not to mention isolation from road conditions and loss of phones and cellphones -- make it difficult or impossible to respond. Some will go home to take care of their own family. This even influences National Guard call-up response rates in disasters and can impact public safety agencies as well.

With similar projections, Bruce Gellin, National Vaccine Program Director at the U.S. Department of Health and Human Services, said that government offices and private businesses "should expect as much as 40 percent of its workforce to be out during a pandemic." He continued that some of these individuals will be sick, dead, suffering depression, caring for a loved one, or just staying home to prevent contracting or spreading the virus.

Hospital disaster plans cannot count on a staff level that equals or exceeds their normal staffing. Your plan should be capable of functioning at scaled levels based on the scope of the emergency and the available staff.

Just as Root Cause Analysis requires that you keep digging by asking "Why?", disaster planning requires that you keep asking "What else could go wrong?."