The forecasters were 284 experts from a variety of fields, including government officials, professors, journalists, and others, with many opinions, from Marxists to free-marketeers.

Since 2011, Tetlock and his wife/research partner Barbara Mellers have been co-leaders of the Good Judgment Project (GJP), a research collaborative that emerged as the winner of the IARPA tournament.

Illustrative questions include "What is the chance that a member will withdraw from the European Union by a target date?"

It involves gathering evidence from a variety of sources, thinking probabilistically, working in teams, keeping score, and being willing to admit error and change course.

Tetlock and Mellers[14] see forecasting tournaments as a possible mechanism for helping intelligence agencies escape from blame-game (or accountability) ping-pong in which agencies find themselves whipsawed between clashing critiques that they were either too slow to issue warnings (false negatives such as 9/11) and too fast to issue warnings (false positives).

[18][19] In his earlier work in this area, he showed that some forms of accountability can make humans more thoughtful and constructively self-critical (reducing the likelihood of biases or errors), whereas other forms of accountability can make us more rigid and defensive (mobilizing mental effort to defend previous positions and to criticize critics).

[20] In a 2009 essay, Tetlock argues that much is still unknown about how psychologically deep the effects of accountability run—for instance, whether it is or is not possible to check automatic or implicit association-based biases,[21] a topic with legal implications for companies in employment discrimination class actions.

This research argues that most people recoil from the specter of relativism: the notion that the deepest moral-political values are arbitrary inventions of mere mortals desperately trying to infuse moral meaning into an otherwise meaningless universe.

People can become very punitive "intuitive prosecutors" when they feel sacred values have been seriously violated, going well beyond the range of socially acceptable forms of punishment when given chances to do so covertly.

Tetlock has advanced variants of this argument in articles on the links between cognitive styles and ideology (the fine line between rigid and principled)[37][38] as well as on the challenges of assessing value-charged concepts like symbolic racism[39] and unconscious bias (is it possible to be a "Bayesian bigot"?).

[40][41][42][43] Tetlock has also co-authored papers on the value of ideological diversity in psychological and social science research.

[44][45] One consequence of the lack of ideological diversity in high-stakes, soft-science fields is frequent failures of what Tetlock calls turnabout tests.

[46][47][48] In collaboration with Greg Mitchell and Linda Skitka, Tetlock has conducted research on hypothetical societies and intuitions about justice ("experimental political philosophy").

[49][50][51][52][53] Hypothetical society studies make it possible for social scientists to disentangle these otherwise hopelessly confounded influences on public policy preferences.