Oregon has been the stage for a number of high-profile search and rescue missions in the past year. Now, Oregon researchers say they have developed a survival prediction model that could help rescue teams make the difficult decision of when to stop searching.

SKY 8

Helicopters fly over the search area.

Emergency medicine researchers at Oregon Health and Science University looked at all 4,244 search and rescue missions initiated in Oregon from 1997 to 2003. They found time was the most important element in determining whether a person would be found alive -- 99 percent of people found alive were found in the first 51 hours after being reported missing.

Little information exists to help searchers determine when to end a search and rescue mission, the researchers said. So they say this model could be used as another tool in planning search and rescue missions.

 Most notable searches in 2006:

Search for James Kim & family

Search for 3 climbers on Mt. Hood

"This is not to say that all searches should be called-off after 51 hours," said Annette Adams, a research instructor in the OHSU Center for Policy and Research in Emergency Medicine. "We believe this is a good first step in using statistical data to develop a rule to help search and rescue teams. With more data, we could use this method to develop a rule for when to abandon a search or change it to a recovery operation."

OHSU says the uncertainty of when to end a search takes an emotional toll on the loved ones of the missing person and the searchers. Ending a search when there is little hope for survival decreases the risk to rescuers and conserves valuable resources.

"Nobody is going to make a decision based on a number alone," said Georges Kleinbaum, search and rescue coordinator for the Oregon Office of Emergency Management. "Most people search long after there is any reasonable doubt the person is alive."

Every search and rescue mission is different, depending on factors like the weather, where the people are missing and what sort of experience they have in the outdoors.

"This kind of information can be useful," he said. "But it doesn't always work that way in real life."

The computer model analyzes several variables from a state database. These include length of the search, the age and gender of missing persons and if the search was conducted by air, land or water. Weather data, including amount of precipitation on the day the search began and minimum and maximum daily temperature, was collected from weather stations near where the search took place.

Dr. Terri Schmidt, professor of emergency medicine at OHSU School of Medicine and a member of the OHSU Center for Policy and Research in Emergency Medicine, said the analysis does have some limitations, such as the inability to look at the medical conditions of the lost individuals or their outdoor experience.

"Intuitively we assume these are significant factors to survival," he said.

The analysis found people reported missing in May through October and those older than 60 were less likely to survive. People reported missing on land were more likely to be found alive than those reported missing in the water.

The findings were published in the most recent edition of Wilderness and Environmental Medicine Journal.