Kidney disease is a low-profile, unglamorous problem, a disease that disproportionately strikes minorities and the poor. Its celebrity spokesman is blue-collar comedian George Lopez, who received a kidney from his wife.

The SAT is not perfect. We all know smart, knowledgeable people who do badly on standardized tests. But neither is it useless. SAT scores do measure both specific knowledge and valuable thinking skills.

Abundant choice doesn't force us to look for the absolute best of everything. It allows us to find the extremes in those things we really care about, whether that means great coffee, jeans cut wide across the hips, or a spouse who shares your zeal for mountaineering, Zen meditation, and science fiction.

The glamour of air travel - its aspirational meaning in the public imagination - disappeared before its luxury did, dissipating as flying gradually became commonplace.

Kidney disease is a low-profile, unglamorous problem, a disease that disproportionately strikes minorities and the poor. Its celebrity spokesman is blue-collar comedian George Lopez, who received a kidney from his wife.

Medicare is immune from the competitive pressures that force private insurers to pay attention to what patients and doctors want.

Progress through trial and error depends not only on making trials, but on recognizing errors.