The TV ratings system is “undergoing one of its most sweeping overhauls since the advent 20 years ago of Nielsen ‘people meters,’ a then-state-of-the-art audience measurement tool that offered more precision than the viewing diaries that participants had filled out for decades. This fall, homes with DVRs make up nearly 20% (compared with 9% last fall) of Nielsen’s national sample of TV viewers — the cohort whose closely scrutinized behavioral patterns are the most important single factor in deciding whether programs live or die.”