PBEE Decision Variable Considerations DISCUSSION PEER TESTBED MEETING 5/23/02

Overall Conclusions  Multiple considerations involved  Relevant considerations will differ among decision makers and decision situations  Consideration of life-safety, functionality (downtime), and repair costs are relevant  Level of information will also vary  By stage in education in decision process  moving from probability of loss of life to more refined probabilistic statements  Moving from scenario based results to probabilistic results  Important to be able to communicate probabilistic aspects and uncertainties

Overall Conclusions  Useful to consider new ways of conveying information  Relative risk considerations as done with medical procedures  Comparative information (relative to events within experience base of client, types of structures)  Specifics of different metrics – getting closer!  Life safety: several different potential measures all relating to probability of loss of life  Functionality: hours/days (time) to restore full functionality, which can then be translated into downtime costs  Repair/damage: cost of repair

Overall Conclusions  Considering probabilistic information  Will depend on decision-maker – many want initially scenario /deterministic results  Multiple ways of communicating probabilistic aspects  Considering uncertainty  Important to consider  Split between notions of level of confidence (e.g., 90% confident), and expressing results as confidence interval (e.g., expected damage within range of $400,000 and $900,000).  Need to consider relevant time horizons for thinking about events and decisions (e.g., for confidence intervals) to the extent these are relevant

Small Group Results  14 individuals participating in PEER breakout  10 structural engineering (4 practicing, rest academic), 4 social science/ management/ architecture/ risk analysis  Filled out short questionnaire with results that follow

Decision Considerations

Communicating Uncertainty

Other Considerations  Individual comments re expressing impacts  Better to talk about exceedance probabilities on an annual basis for particular kinds of impacts – providing distributions across different facilities.  Often asked to give an overall rating of “life safe” to a building (with uncertainties embedded into this judgment)  Externalities almost never considered  Individual comments re expressing probabilities  Better to talk about probability of given level of loss on an annual basis  Requires sophisticated client to present probabilistic results  Individual comments re expressing uncertainties  Engineers more comfortable expressing range of potential losses (confidence interval) rather than a single confidence value.  Requires sophisticated client to present probabilistic results