Life is never as stark and simple as the politicians paint it. Only incumbents can campaign on how great things are going. Change sells as a moving force because it promises something better. Even conservatives, eager to conserve and protect the good things of the past, argue for improving things at home and abroad. But nobody wants to charge headlong into the unknown.

Criticisms and predictions carry risks. Silver linings tarnish, and the pot of gold disappears as the rainbow vanishes. The iron law of unintended consequences usually means the cure was at least as bad as the disease, and sometimes worse. But there are exceptions. John McCain was as harsh with his criticism of the Iraq war as Donald Rumsfeld fought it, but now concludes that "the surge" is working. Other good news follows.

A number of social indicators, both national and international, suggest that doom and gloom criers have never been more wrong than they are today. Prospect, a liberal magazine, and Commentary, a conservative journal, find cheerful cultural trends and challenge predictions of downward slides foreseeing an America weak and demoralized. In a number of key categories of crime, teenage drug use, abortion, educational achievement and welfare rolls, the statistics are positive. The dark diagnoses and gloomy speculations of a decade ago are rendered wrong (and wrongheaded).

While one explanation does not fit every change for good, Congress is entitled to some of the credit. "The 1996 welfare-reform bill was the most dramatic and successful social innovation in decades, reversing 60 years of federal policy that had long since grown not just useless but positively counterproductive," write Peter Wehner and Yuval Levin, fellows at the Ethics and Public Policy Center, in Commentary magazine. The dire predictions that welfare reform would merely accelerate the spread of poverty have been proved wrong, wrong, wrong. Poverty declined. The five-year term limit on federally funded benefits created incentives for millions of men and women to find work, lending newfound dignity and raising family incomes.

Michael Lind, a senior fellow at the New America Foundation, echoes this assessment in Prospect, citing sharp improvement in countering violent crime and teenage drug abuse. Ethnic rivalries that were going to tear America apart, setting race against race and leaving the land Balkanized like Yugoslavia, were wrong. Time and racial tension mellowing, even unto interracial marriage, have put the melting pot simmering again. Half of all Asian Americans marry outside their race, and the number of white-black unions is increasing, though at a slower pace. (Romance always finds a way around obstacles, high or low.) The polarization of speech is subsiding: Only 10 percent of second-generation Hispanics speak only Spanish; almost half of second-generation Hispanics speak no Spanish at all. Not all unforeseen consequences are bad.

The Economist magazine goes further in qualified optimism, looking past the forecasts of economic uncertainty to discover a world that is "unexpectedly prosperous and peaceful." The men and women who go to bed hungry, or who are brutalized by tyrannical regimes can't sup on statistics, of course, but "the world seems to be in rather better shape than most people realize."

Many more people have access to clean water, for example. In South Asia, the numbers of those who must drink dirty water have been cut in half over two decades. As a result, the statistics of child mortality is down dramatically. UNICEF, the United Nations organization that tracks child welfare worldwide, reports that in 2007, for the first time in modern history, fewer than 10 million children died before the age of five. The death of any child is a tragedy, and these deaths have declined by 25 percent. Literacy is on the rise; now, nine-tenths of those between the ages of 15 and 25 can read and write.

The economic inequalities are often blamed on globalization, but different rates of technological progress account for many disparities. No one wants to limit technological progress (only fools would try). It's more important to find ways to spread the benefits of technology.

Statistics can't feed the hungry, heal the sick or prevent terrorism and genocide, but statistics can focus the mind on managing change, and rally us to do what we can, and do it where it counts. There was a song for it in the 1940s: "You've got to accentuate the positive, eliminate the negative, latch on to the affirmative, don't mess with Mister In-Between."