CHICAGO - When Jon D. Miller looks out across America, which he can almost do from his 18th-floor office at Northwestern University Medical School in Chicago, he sees a landscape of haves and have-nots - in terms not of money, but of knowledge.
Dr. Miller, 63, a political scientist who directs the Center for Biomedical Communications at the medical school, studies how much Americans know about science and what they think about it. His findings are not encouraging.
While scientific literacy has doubled over the past two decades, only 20 to 25 percent of Americans are "scientifically savvy and alert," he said in an interview. Most of the rest "don't have a clue." At a time when science permeates debates on everything from global warming to stem cell research, he said, people's inability to understand basic scientific concepts undermines their ability to take part in the democratic process.
Over the last three decades, Dr. Miller has regularly surveyed his fellow citizens for clients as diverse as the National Science Foundation, European government agencies and the Lance Armstrong Foundation. People who track Americans' attitudes toward science routinely cite his deep knowledge and long track record.
"I think we should pay attention to him," said Eugenie Scott, director of the National Center for Science Education, who cites Dr. Miller's work in her efforts to advance the cause of evolution in the classroom. "We ignore public understanding of science at our peril."
Rolf F. Lehming, who directs the science foundation's surveys on understanding of science, calls him "absolutely authoritative."
Dr. Miller's data reveal some yawning gaps in basic knowledge. American adults in general do not understand what molecules are (other than that they are really small). Fewer than a third can identify DNA as a key to heredity. Only about 10 percent know what radiation is. One adult American in five thinks the Sun revolves around the Earth, an idea science had abandoned by the 17th century.
At one time, this kind of ignorance may not have meant much for the nation's public life. Dr. Miller, who has delved into 18th-century records of New England town meetings, said that back then, it was enough "if you knew where the bridge should be built, if you knew where the fence should be built."
"Even if you could not read and write, and most New England residents could not read or write," he went on, "you could still be a pretty effective citizen."
No more. "Acid rain, nuclear power, infectious diseases - the world is a little different," he said.
It was the nuclear power issue that first got him interested in public knowledge of science, when he was a graduate student in the 1960's. "The issue then was nuclear power," he said. "I used to play tennis with some engineers who were very pro-nuclear, and I was dating a person who was very anti-nuclear. I started doing some reading and discovered that if you don't know a little science it was hard to follow these debates. A lot of journalism would not make sense to you."
Devising good tests to measure scientific knowledge is not simple. Questions about values and attitudes can be asked again and again over the years because they will be understood the same way by everyone who hears them; for example, Dr. Miller's surveys regularly ask people whether they agree that science and technology make life change too fast (for years, about half of Americans have answered yes) or whether Americans depend too much on science and not enough on faith (ditto).
But assessing actual knowledge, over time, "is something of an art," he said. He varies his questions, as topics come and go in the news, but devises the surveys so overall results can be compared from survey to survey, just as SAT scores can be compared even though questions on the test change.
For example, he said, in the era of nuclear tests he asked people whether they knew about strontium 90, a component of fallout. Today, he asks about topics like the workings of DNA in the cell because "if you don't know what a cell is, you can't make sense of stem cell research."