Environmental Decision Scenarios



Environmental Decision Scenarios

Decision Framing

The following Decision Scenarios can be used in conjunction with lessons that incorporate understanding of risk, assessment of risk, or predictive value of scientific data. They can be used as individual questions or as group discussion exercises. Underlying this assessment is the assumption that good decision making is invariant to the way objective data are presented; students should arrive at similar conclusions regardless of how the information is framed. Therefore one measure of a student’s decision making skill is to test their sensitivity to framing effects. The sensitivity is examined across the class, rather than within a student. Thus, this type of assessment has the additional advantage that it can then be used to further discussion on how to use and interpret data.

Examples for Testing Sensitivity Framing: For the following decision scenarios, students receive a scenario and the data from the risk analysis either positively framed or negatively framed.

Problem 1: Storage of Hazardous Waste

The storage of radioactive waste is an important environmental problem confronting the United States. Because of the complexity of this problem, it is likely to be many years before any long term storage program is operating. Thus we must develop a strategy for the temporary storage of the waste. Two possible options have been proposed. In the first, all the existing waste would be shipped to a central location which would be responsible for storing the waste until a long term solution is developed. The second option involves developing improved temporary storage facilities and regulations at the locations where the waste is generated. Results of risk analyses suggest that while the storage of the waste at a centralized location is safer than having it dispersed at numerous different sites, there is a risk that an accident could occur during the transportation of the waste to the central storage site. In particular, the risk analyses indicate that:

Positive Framing

If the centralized storage proposal is adopted, there is a 90% chance that all the waste will be transported to the centralized storage safely, a 68% chance the waste will be safely stored after ten years, and a 34% chance the waste will be safely stored after 100 years.

If the dispersed storage proposal is adopted, all the waste will be initially stored safely, there is a 77% chance the waste will be safely stored after ten years, and a 22% chance the waste will be safely stored after 100 years.

Assuming that the risk analyses are accurate, which temporary storage option do you prefer?

Negative Framing

If the centralized storage proposal is adopted, there is a 10% chance that an accident will occur while the waste is being transported to the centralized storage area, a 32% chance that an accident will have occurred after ten years, and an 66% chance that an accident will have occurred after 100 years.

If the dispersed storage proposal is adopted, no accidents will occur as the waste is initially stored, there is a 23% chance an accident will occur after ten years, and a 78% chance that an accident will have occurred after 100 years.

Assuming that the risk analyses are accurate, which temporary storage option do you prefer?

Cognitive Analyses:

From the immediate storage perspective, dispersed storage is more attractive when its advantage is stated as a reduction of risk of accident from 10% to 0% rather than as an increase in safe storage from 90% to 100%. People tend to make proportional rather than absolute quantity comparisons. From a long-term storage perspective, the centralized storage has the more attractive outcome, although this case is frequently under-emphasized given that in either the positive or negative framing a proportional comparison is not meaningful. Example shows a failure of invariance, i.e., although both framings are statistically equivalent, people display a systematic bias in their decisions that depends on the framing. In other words, the decision outcome differs as a result of the framing. The notion of invariance is a key component of standard cognitive models of decision making based on the idea that people make rational decisions (in particular, expected utility theory). While the definition of rationality is controversial, there is general agreement that rational thought requires invariance.

Problem 2: Earthquake Hazard

A large earthquake is projected to occur near a populated area in southern California sometime in the next 25 years. It is projected that the earthquake will kill 600 people. Two alternative programs to reduce the earthquake hazard have been proposed. Assume that risk analyses of the programs suggest that:

Positive Framing

If program A is adopted, 200 people will be saved.

If program B is adopted, there is a 1/3 probability that 600 people will be saved, and 2/3 probability that no people will be saved.

Which of the two programs would you favor?

Negative Framing

If program C is adopted 400 people will die.

If program D is adopted there is 1/3 probability that nobody will die, and 2/3 probability that 600 people will die.

Which of the two programs would you favor?

Cognitive Analyses:

Both cases are statistically equivalent, yet the majority choice in the positive framing is for the risk averse saving of 200 people, while in the negative framing the majority choice is the risk seeking possibility that no one will die. This is another example of failure of invariance and demonstrates the tendency for people to be risk averse for gains (would rather have a sure gain than risk of a lower gain) and risk seeking for losses (would avoid a sure loss if chance of a lesser loss). The shift in opinions is caused by a shift in reference point accomplished by the mere labeling of the outcomes: saving lives in the positive frame and dying in the negative frame. Thus this is an example of how framing can result in decision variance.

Pedagogical Use of Decision Scenarios

1. How can instructors enhance student understanding of data, in this case data related to risk assessment?

a. Role-playing exercises and/or small group discussions may increase the likelihood that students consider the alternate framing of the data, even when it is not explicitly presented (e.g., “well, if there 10% chance that an accident occurs that means there is a 90% chance that no accident will occur). Awareness of both frames generally leads to less decision variance.

2. Decision scenarios can be indicators of understanding of the predictive, albeit uncertain, information scientific instruments may provide. For example, students may be interpreting data from three instruments monitoring a volcano, a geodimeter, a correlation spectrometer (cospec), and a seismometer. The readings from the instruments can, in turn, be used within a role-playing or decision scenario where students decide when and if to evacuate villages near the volcano.

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