Health care aside, the deadweight loss in question is not that large.

Judged as of 2019-07-18, in the context of Cowen's remarks (probably on the deadweight loss from US monopoly power or market concentration, leaving health care aside). True: mainstream economic estimates available by 2019 put that deadweight loss outside health care at a small share of GDP (around 1% or less). Mostly true: most estimates are small, with a few credible higher ones. Mixed: estimates vary widely, with credible studies finding both small and large losses, so the matter is unsettled. Mostly false: the claim relies on older low estimates (e.g. Harberger-style), while newer credible work by 2019 mostly found substantial losses (several percent of GDP). False: the established evidence by 2019 clearly showed a large deadweight loss outside health care.

Set before the research began.

1. E1 The 'Welfare Loss from Monopoly' Re-visited (CEWP 20-13) Carleton University Economics Working Papers (Richard Carson) · August 2020

   “In general, the results of these studies varied widely and showed welfare losses that were often many times Harberger's estimate, although not necessarily large as a share of GNP or GDP.”

2. E2 The 'Welfare Loss from Monopoly' Re-visited (CEWP 20-13) Carleton University Economics Working Papers (Richard Carson) · August 2020

   “In a 1954 paper, A.C. Harberger claimed that the welfare loss from monopoly in U.S. manufacturing was less than .1% of national income over 1924-1928.”

3. E3 Are Markets Becoming Less Competitive? Federal Reserve Bank of Richmond · 6 June 2019

   “A recent study found that "the welfare costs of markups are large," primarily because they act as a tax on output.”

4. E4 Are Markets Becoming Less Competitive? Federal Reserve Bank of Richmond · 6 June 2019

   “It may be too soon to reach a decisive conclusion about whether market power, not simply market concentration, is on the rise.”

E1 reviews the literature and finds that estimates of the welfare loss from monopoly "varied widely": they were often many times Harberger's figure but "not necessarily large as a share of GNP or GDP". E2 records Harberger's original estimate as below 0.1% of national income. In contrast, E3 (June 2019) cites a recent study that found "the welfare costs of markups are large". E4 says it may be too soon to reach a decisive conclusion about whether market power, not simply market concentration, is on the rise. Taken together, the evidence shows credible estimates both small and large, so as of 2019 the question was unsettled, which matches the "mixed" criterion.