Judgment and Decision Making

9

ASSESSING UNCERTAINTY IN PHYSICAL CONSTANTS

Max Henrion

CARNEGIE MELLON UNIVERSITY, DEPARTMENT OF ENGINEERING AND PUBLIC POLICY, PITTSBURGH, PENNSYLVANIA 15213

Baruch Fischhoff

DECISION RESEARCH, A BRANCH OF PERCEPTRONICS, 1201 OAK, EUGENE, OREGON 97401

Abstract

Assessing the uncertainty due to possible systematic errors in a physical measurement unavoidably involves an element of subjective judgment. Examination of historical measurements and recommended values for the fundamental physical constants shows that the reported uncertainties have a consistent bias towards underestimating the actual errors. These findings are comparable to findings of persistent overconfidence in psychological research on the assessment of subjective probability ...