Judges indeed play a central role in the American legal system—
more so than in most others. But the behavior of American judges, and
in particular the determinants of their decisions, are not well understood,
including by lawyers, law professors, and even many judges (we’ll explain
that paradox in due course). In part this is because judges in our system
are permitted to be, and most are, quite secretive.2 Indirect methods must
be employed to understand their behavior. Beginning more than half a
century ago but accelerating in recent
scientists in particular, but also economists and psychologists, and, increasingly,
academic lawyers knowledgeable about social science—have
used ever more sophisticated theoretical concepts and quantitative tools
to penetrate self-serving judicial rhetoric,