Let's start the discussion obliquely by pointing out that science education in the United States probably could do with a thorough make-over. It's not a huge secret that the majority of Americans are under-developed in their ability to understand science. According to the United States National Center for Education Statistics, "scientific literacy is the knowledge and understanding of scientific concepts and processes . . . " Our schools do a better job of forcing kids to ingest facts that they do of establishing processes.
So, with that as a starting point, if becomes unsurprising that anything stamped with the "Done by a REAL Scientist" label in the media gets treated with immediate deference. For most of their educational career, children have been lectured (or hectored, depending on topic) on science while lip service was done for getting them to both understand and use the scientific method.
When it comes time to decide whether to swallow something patently absurd, or to apply critical thinking skills and a healthy dose of skepticism, the default is to follow the lead of the authority figure which, in this case, is the scientist.
Even one who puts out a study, as Dr. Johannes Bohannon did, stating that eating a chocolate bar on a low-carb diet accelerated weight-loss.
"There are smart people out there who are getting fooled by this stuff because they think scientists know what they're doing."
Those are the words of Bohannon after his 'study' - the data and methods were deliberately falsified - went viral. It was good news, and people wanted to believe. And a scientist said so. The science is settled.
This happens not just in the food and health field, which has seen eggs go from shell-encased heartaches to okay, margarine from savior to second place in the butter sweepstakes, and the recent news that cholesterol in the diet may not be such a big deal. It happens in pesticides (killing bees in Europe), vaccinations (causing autism), and cellphones (causing brain cancer).
So, back to the question that started this whole thing. How can you tell if a scientist is lying?
First, remember the old saw, "If it's too good to be true . . . " In science, this is called skepticism, a term that unfortunately has been co-opted into a negative by the forces of climate change policymakers.
A good scientist is inherently a skeptic. Without that trait, the normal investigative process they pursue gets short-circuited. With it, they develop a hypothesis, test it, and see how the data supports or fails to support the initial idea. If the data does not support the hypothesis, they change the hypothesis.
A bad scientist changes the data, or in the case of NOAA, renormalizes it to make unfortunate results disappear. In the case of the recent scandal regarding the study by Michael LaCour that appeared to support gay marriage, the results were falsified in their entirety.
In a perfect world, the out-right frauds would be quickly caught as other scientists tried to replicate the studies. Sadly, that doesn't happen often enough. To help, Stanford opened the Meta-Research Innovation Center which is systematically identifying problems in medical research.
Second, if it appears that legitimate concerns about a fact or study get answered by invective instead of data, it is a pretty good sign that someone has an agenda that is more important than the pursuit of knowledge.
Finally, remember the adage first offered by Nobel Laureate (in Physics) Murray Gell-Mann, dubbed the Gell-Mann Amnesia Affect. Apply to all instances in which a person appeals to the authority of an 'expert'.
"Briefly stated, the Gell-Mann Amnesia effect is as follows. You open the newspaper to an article on some subject you know well. In Murray's case, physics. In mine, show business. You read the article and see the journalist has absolutely no understanding of either the facts or the issues. Often, the article is so wrong it actually presents the story backward—reversing cause and effect. I call these the "wet streets cause rain" stories. Paper's full of them.
In any case, you read with exasperation or amusement the multiple errors in a story, and then turn the page to national or international affairs, and read as if the rest of the newspaper was somehow more accurate about Palestine than the baloney you just read. You turn the page, and forget what you know.”