What does this mean in simple terms?
"Disaster planning is an illusion unless it is based on valid assumptions about human behavior, incorporates an interorganizational perspective, is tied to resources, and is known and accepted by the participants" ~ Erik Auf der Heide
Take the quote one part at a time, and then put the parts back together.
"Disaster planning is an illusion unless" - The creation of a disaster plan means nothing unless certain conditions are met. To say that there is a plan in place without the conditions listed being fulfilled is a farce; the community that says it has a plan without all of these qualifications is fooling itself.
"Based on valid assumptions about human behavior" - Any planning for a disaster needs to account for the probable actions of the humans affected by the disaster. Disaster planners will need to understand that persons in a disaster may react with panic and attempt to flee the area; may retreat to what they perceive as a safe location and refuse to leave, even when ordered to do so, with the result that they require emergency evacuation at a later time; may become irrational or impatient due to the stress of the situation, and other such predictable behavior patterns.
"Incorporates an interorganizational perspective" - Disaster planning is most efficiently planned and executed when responsibilities are divided and assigned to a variety of groups or organizations, utilizing the resources of each organization to address needs for which it is particularly suited. This means the disaster plan should include procedures for the health care providers in the affected area to establish first aid centers, triage and surgery facilities, and so on; the law enforcement authorities should be aware of areas assigned to various local authorities, should know procedures required to request additional personnel if needed, and should have plans in place to enact curfews or other legal restrictions as necessary; utility companies should have procedures developed to address power outages, water supply interruptions, and other basic services that may need restoration; and so on. When organizations plan how their responses will be coordinated to address all critical issues, the response to the disaster will be more effective and timely.
"Is tied to resources" - Assumptions about how quickly utilities can be restored or how soon all fires may be extinguished have to be based on realistic assessment of resources available to address the needs. Planning for disaster response needs to acknowledge that there may be limited availability of services or personnel to meet all needs in all locations in the immediate aftermath of a disaster.
"Is known and accepted by the participants" - Once disaster plans have been developed for a region, they need to be distributed to all the organizations that may be involved so those organizations can conduct training and carry out preparation of equipment and materials. Members of the public need to be made aware of evacuation routes, locations of emergency shelters, and procedures for abandoning their dwellings - and they need to be willing to follow the procedures if it becomes necessary.
It's not a simple process, so it's not something easily explained in simple terms.