In 2004, Robinson prepared this article for Health Affairs. The author writes:

This paper presents data on 50 state and substate insurance markets, in terms of the 2003 relative shares of the largest health plans and the antitrust index of concentration. It presents 2000–2003 data on rates of growth in premiums, costs, operating earnings, returns on equity, and share prices for the nation's largest health plans (WellPoint, Anthem, United, Aetna and CIGNA). Private insurers face renewed price and profit pressures in the short term, but long-term prospects depend on the emergence of new products and new competitors in an increasingly consolidated industry.

In 2007, this article was selected again for inclusion in a special issue of Health Affairs, the editor notes:

The managed care revolution of the 1980s created innumerable new health plans, mostly HMOs, that challenged the long dominance of Blue Cross and indemnity carriers. By the 1990s, intense competition had driven much of the industry into financial losses, spurring mergers and acquisitions that left an ever smaller number of ever larger competitors. By late 2004, when James Robinson combined data from all lines of commercial health insurance, he found most markets dominated by three or four carriers. Consolidation had permitted steep premium increases, returning the industry to profitability and rekindling investor interest. Robinson outlined two possible futures: Either new firms with new products, such as consumer-directed health plans, would create renewed competition, or—as actually occurred—consolidation would continue, but enrollment would increasingly shift to public programs that contracted with the private insurers. Since Robinson wrote this paper, many private consumer-directed health plans have grown slowly or have been acquired by the major carriers, while enrollment in Medicaid managed care and Medicare Advantage continues to increase.