What happens when you put the life of the mind and the problems of a global civilization in a jar and shake it? The powerful and sometimes uneasy alliance between science and the society it serves is the theme of this year's special report on the “State of the World's Science.”

We start with the phenomenon of Big Science, which occurs when society deems an area of research important enough to throw money and resources at it. But the goals and methods of research scientists and politicians can be difficult to sync up. In “Trouble in Mind,” journalist Stefan Theil looks at the travails of the Human Brain Project, a vast research program that the European Commission established in 2013 to advance the field of neuroscience and boost European research. Theil shows what can go wrong when a top-down funding bureaucracy tries to orchestrate the unpredictable progress of scientific discovery.

Science is increasingly called on to develop social programs that evaluate evidence with some rigor. Years ago Dean Karlan asked a naive question about microlending initiatives, which showed promise as a tool for lifting people out of poverty: How do we know they really work? He never got a satisfying answer, and it bugged him. Since then, Karlan, now at Yale University, has endeavored to bring the methods of science to bear on assessing the effectiveness of poverty-fighting programs. In “More Evidence, Less Poverty,” he describes his search for a science of ending poverty and discusses what has been proved successful so far.

Rodrigo Guerrero Velasco conducted his social science research from an unusual vantage point: city hall. Twice mayor of Cali, a city of now more than two million people in Colombia, Guerrero Velasco was in a position to bring a measure of scientific method to governance. In particular, he sought to tackle an epidemic of violent homicides using methods based on evidence. Drawing on his graduate education in epidemiology at Harvard University, he crafted a program that entailed posing hypotheses about the causes of crime, implementing policies to address them and testing to see if they worked. The results were so dramatic that Guerrero Velasco's approach became a model for Colombia's capital city Bogotá and elsewhere.

We round out the section with a graphical snapshot of the top research nations and institutions around the world, powered by the Nature Index of the scientific literature. (Scientific American is part of Springer Nature.) The results, we hope, will surprise and delight you.