Uncertainties about Uncertainty
Cliff Mass
Major Issues
Are People Basically:
Deterministic
Probabilistic
A Little of Each?
Deterministic Evidence
• People seem to prefer deterministic
products: “tell me exactly what is going to
happen”
• People complain they find probabilistic
information confusing
• Media and internet not moving forward
very quickly on this.
An attempt… I suspect 99% of the people don’t understand
Probabilistic Evidence
• We often interact with our surroundings in a
probabilistic way.
• As we walk into a new environment we are
constantly updating information,
speculating on what/who an object is,
reducing the possibilities ….
We are highly attracted to games
of chance
And seem comfortable enough with odds…
Perhaps... An approach that will
work
We are also used to probabilities
in medicine
The pills
have a 90%
chance of
working
Feedback
• Some people like to read forecast
discussions or listen to a TV forecast
analyze the situation to determine the
uncertainty in the forecast.
The Statistic Prediction
Infrastructure is Still Not in Place
• NCEP is way behind the times
• The U.S. lacks reliable and reasonable sharp
prediction of PDFs of major variables.
• We are making progress, but we still have far to go
for local BMA for all basic parameters.
• What about for derived parameters..such as
visibility and ceiling?
• Verification is still primitive.
But even if we had the statistical
engine to produce good pdfs
• In the end, people and industries have to make a
deterministic decision…to do or not do something.
• The biggest problem is to help people go from
pdfs and probabilistic information to decision
making. They need a model or tool or application
to do so?
• Imagine a new type of generic decision-making
application that walks them through it..
Web-Based Decision Aid
• Welcome, let me help you make your weather
decision.
• Are you concerned about one time or for a period
of time?
• What weather parameter is of concern?
List shown
• For your activity, what range of that parameter is
acceptable?
• If the forecast is wrong how much would it cost
you?
• Do you have so spend money to protect against a
wrong forecast? If so, how much?
Decision Aid
• Here is a summary of what you told us:
• Hit return to see the optimal decision based
on your information.
Decision Aid
• You should do the activity. There is only a
5% chance you will not be able to complete
it.
• If we greedy…
– May we suggest that you ….
Determining How People Think
• Do we really know how people process,
interpret, and use probabilistic information?
• What will encourage them to use it?
• Susan and others have started, but clearly
far more to do.
• Do people use probabilities differently or
better/worse for extreme events?
The Future … and the End