During the past half century many nations have adopted policies whose function is to discourage cartels and other restrictive practices. Industrialized nations led the movement toward pro-competition policies, but more recently, developing nations have begun to join the parade. Initial steps...

This paper considers factor estimation from heterogenous data, where some of the variables are noisy and only weakly informative for the factors. To identify the irrelevant variables, we search for zero rows in the loadings matrix of the factor model. To sharply separate these irrelevant...

We analyze the effects of the 1984 breakup of the Bell System on the rate, diversity, and direction of US innovation. In the antitrust case leading to the breakup, AT&T, the holding company of the Bell System, was accused of using exclusionary practices against competitors. The breakup was...