Whyte, Wang & Cai's 2015 essay and Greenhalgh's 2003 article, without citing each other, divide 1971-1980 into the same three-stage timeline

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Whyte, Wang & Cai's 2015 essay states: "In 1971, China's State Council approved a report on birth control, setting the goals of reducing the annual rate of population growth"; that "highly coercive birth planning enforcement was already the order of the day during the 1970s... preceding the launching of the one-child policy" in 1980; and that "already in 1978, the Chinese leadership began contemplating the need for a one-child policy." Greenhalgh's 2003 Population and Development Review article, read past the single passage the vault's existing note on it quotes, states: "Much evidence suggests that between mid-1978 and mid-1979, China's top leaders and population policymakers were moving toward adoption of a policy encouraging one-child families. At its first meeting in June 1978, the newly revamped Birth Planning Leading Group... recommended that 'it is best to allow only one birth, two are the most, and third births must be strictly controlled'" (p. 185), and that "in mid-September 1980 the third session of the Fifth National People's Congress gave its seal of approval to a new policy" via an "Open Letter dated 25 September," after which "the one-child policy was effectively set in political stone" (pp. 184-186).

The two essays — an American-sociology synthesis and Greenhalgh's own primary ethnographic-historical article, which never cite each other — independently land on the same three-stage shape: an intensifying coercive campaign from 1971 (the "later, longer, fewer" campaign); a pre-launch period in which the leadership moves toward a one-child rule; and a formal national launch in 1980. The convergence is on the shape and the years, not on the evidence, and the two accounts are pitched at different resolutions: Greenhalgh dates the middle stage "between mid-1978 and mid-1979" and anchors it to the June 1978 leading-group recommendation, where Whyte, Wang and Cai say only that "already in 1978, the Chinese leadership began contemplating the need for a one-child policy" and never mention that meeting at all; Greenhalgh dates the launch to the September 1980 NPC session and the Open Letter of 25 September, where Whyte, Wang and Cai give only the year. Neither document's own citations connect it to the other (the vault's companion finding); the convergence is structural, arrived at from separate research, not a shared source.