Song Jian's 1978 self-report — cited to a 1986 essay, quoted by Greenhalgh in 2003 — was in print five years before the book that triggered Olsder's account, and 21 years before that account was ever published

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Geert Jan Olsder's account of a 1975 conversation with Song Jian and Song's own 1978-dated self-report are usually read as two memories that happen to disagree. Sequencing them by publication date instead of event date changes the shape of the comparison. Susan Greenhalgh's Population and Development Review article, which quotes Song's own words dating his first exposure to population-systems-analysis to "a visit to Europe in 1978," was published in June 2003. Her book [[entity-just-one-child-greenhalgh-2008|Just One Child]] — the book that, on Olsder's own telling, named him and Kwakernaak and prompted the 2008 Trouw approach that produced his realization — was published five years later, in 2008. The account of the 1975 conversation itself, in the only form this vault holds it, was not published until the 2024 U-Today interview: sixteen years after Olsder's 2008 realization, twenty-one years after Song's 1978 dating appeared in Greenhalgh's article, and thirty-eight years after the 1986 essay she cites that dating to (Song 1986: 2–3; "Systems science and China's economic reforms," in Yang Jiachi, ed., Control Science and Technology for Development, Oxford: Pergamon, per the 2003 article's own bibliography, p. 195).

The contradicting evidence therefore did not arise in response to, or in competition with, Olsder's story. It was already fixed in a peer-reviewed scholarly record before the book that prompted Olsder to assemble his account had even been published, let alone read by him. This does not touch the standing hedge on either side — Song's own 1986 essay remains unread beyond Greenhalgh's quotation of it, and Olsder could in principle have described his group's research to Song in 1975 without it registering as the specific "systems analysis theory" epiphany Song dated to 1978 in his own later retrospective, itself subject to the same decades-long haze as any recollection. What changes is the shape of the asymmetry: not two old memories arm-wrestling across a symmetric gap, but one documented, pre-existing self-report and one account built afterward, in response to material connected to the very author who had already published that self-report.