As open journals become intellectual successes, they will come to substitute for subscription-based journals. The entry of two new journals specializing in economic theory, one a commercial subscription journal and the other an open journal, stimulates the question: What does a new journal require in order to achieve intellectual impact? Regressing the ISI Impact Factor for 141 journals on attributes of the journals estimates their relative importance. The intellectual reputations of the editors and of the authors? prior work along with the number of libraries that hold the title are positively associated with the journal?s Impact Factor. Using the attributes of the new journals in the estimated relationships yields a forecast of the Impact Factor for the new journals. An open journal has the advantage of being immediately as accessible everywhere on the Internet as though held by many libraries. Its forecast impact is comparable to the journals with the highest impact in this specialty. Some open journals are able to attract outstanding editors and authors with the natural advantage of universal access without charge.