Generations of American intellectuals became Marxists and believed in the Soviet Union's economic growth powers because of fake news put into books.

Judged as of 2019-07-18, against historical scholarship. True: historians document that significant numbers of American intellectuals across more than one generation adopted Marxist views and/or believed the Soviet Union could deliver superior economic growth, and that false or misleading accounts published in books (for example glowing travel accounts, works by fellow travellers, or textbooks using inflated Soviet growth figures) were a major documented cause of this. Mostly true: both the beliefs and the influence of misleading books are documented, but the claim overstates the scale (for example 'generations' or 'Marxists' rather than sympathisers). Mixed: the beliefs are well documented, but scholarship treats misleading books as only one of several comparable causes. Mostly false: the beliefs are documented, but the causal role of false content in books is unsupported or minor next to other causes (ideology, the Depression, official Soviet statistics passed on in other channels). False: the evidence shows that no significant American intellectual cohort held such beliefs.

Set before the research began.

1. E1 Soviet Growth and American Textbooks: The Endogenous Past UR Scholarship Repository (University of Richmond); article in Journal of Economic Behavior & Organization, vol. 78, 2011 · April 2011

   “Between 1960 and 1980 American economics textbooks overestimated Soviet growth. They held that the Soviet economy was growing faster than the US economy and yet they kept the ratio of Soviet–US output constant over two decades.”

2. E2 Political Pilgrims - Wikipedia Wikipedia · 26 July 2015

   “He answers that part of the reason lies in the ability of Soviet authorities not merely to produce elaborately faked areas for show, but to welcome Western writers, house them comfortably, feed them well, and "above all," flatter them.”

3. E3 Why Were American Econ Textbooks So Pro-Soviet? - Econlib Econlib (Library of Economics and Liberty) · 29 December 2009

   “I demurred. The real problem, I said, was left-wing bias.”

4. E4 The Soviet Economy Was Not Growing; It Was Dying | The Daily Economy The Daily Economy (Foundation for Economic Education-style think-tank publication) · 10 January 2020

   “Even as American economists rejected the Marxist philosophy behind Soviet planning, they settled into a curious postwar habit of disseminating economic projections that depicted the Soviet economy overtaking the United States in the near future.”

The evidence shows that American textbooks overestimated Soviet growth [E1] and that economists projected Soviet overtaking [E4], with other factors also suggested [E2][E3]. It does not document intellectuals becoming Marxists, and it does not show whether books were a comparable cause or a minor one, so it cannot separate "mixed" from "mostly false".