Precision and Accuracy

I remember from my first class in surveying, yes I took a class in surveying somewhere in the Catskills, we were told the difference between precision and accuracy. Precision is how detailed is your measurement, say in feet, 2.00136 feet. Accuracy is a measure as to how close to reality is that precise measurement. One can have great precision and horrible accuracy. People feel comfortable with precision. People are clueless about accuracy. Tell a patient that they have six months to live, and they can deal with it, horrible as it may be. Tell a patient that he has a 20% chance of survival, and the patient always thinks they are in the 20%.

Now to climate change or whatever it is called today. Stanford has an interesting piece on this issue. They note:

“Scientists who acknowledge that their predictions of the future cannot be exactly precise and instead acknowledge a likely range of possible futures may bolster their credibility and increase acceptance of their findings by non-experts,” said ...a Stanford professor of communication and of political science and a co-author on the paper. “But these gains may be nullified when scientists acknowledge that no matter how confidently they can make predictions about some specific change in the future, the full extent of the consequences of those predictions cannot be quantified.”

 They continued:

To find out, the researchers asked half of their respondents to read a second statement acknowledging that the full extent of likely future damage of sea level rise cannot be measured because of other forces, such as storm surge: “Storm surge could make the impacts of sea level rise worse in unpredictable ways.” The researchers found that this statement eliminated the persuasive power of the scientists’ messages. When scientists acknowledged that storm surge makes the impact of sea level rise unpredictable, it decreased the number of participants who reported high trust in scientists by 4.9 percentage points compared with the participants who only read a most likely estimate of sea level rise. The findings held true regardless of education levels and political party affiliation. Not all expressions of uncertainty are equal, ... said: “Scientists may want to carefully weigh which forms of uncertainty they discuss with the public. For example, scientists could highlight uncertainty that has predictable bounds without overwhelming the public with the discussion of factors involving uncertainty that can’t be quantified.”
 
What is most compelling  is that none of the curves we see promulgated have any error bands in them, NONE. What is the accuracy of the thermometer in 1886, 1929, today. Take sea level. One may logically ask; is the sea rising or the land sinking? Good question. We know that the outer banks move, they are plastic in nature, sand like plasticity. Can we measure rising versus sinking? Perhaps, but not with the accuracy we require. Back to accuracy again.

The problem is that for those of us who have spent their careers dealing with uncertainty, we accept it as a matter of course. However that group who accept it as day to day are not the rest of society. Indeed the climate folks need to be truly honest about their data, put some error bounds on them so we can understand, and "I don't know" is also a good answer.