Karni is the Scott and Barbara Black Professor of Economics at Johns Hopkins University.
Karni began his academic career at Tel Aviv University in 1972, where he attained the rank of full professor.
[2] Karni's main contributions are in the fields of individual decision making under uncertainty, social choice theory and the economics of information.
In the field of decision-making under uncertainty, he has worked on the measurement of risk aversion,[3][4][5][6] the modeling state-dependent preferences[7] and the definition of subjective probability,[8] the modeling of awareness and awareness of unawareness[9] and the introduction of the notion of ‘reverse Bayesianism’.
[10] In the field of social choice theory Karni's contributions include the axiomatization and representation of individual behavior that is motivated, in part, by a sense of fairness and interpersonal comparisons of variations in well-being.