BACKGROUND: A chart indicating the likelihood of conception linearly declining with age (86% for women aged 20-24, 78% for 25-29, 63% for 30-34, 52% for 35-39, 36% for 40-44, 5% for 45-49, and 0% for 50 and over) is widely used on Internet fertility sites and by medical professionals. Its origin has been unknown until now. OBJECTIVE: To explore the origin of the chart. METHODS: A literature survey. RESULTS: Among the seven points on the curve, three are based on data that are not the likelihood of conception, while four are probably derived from oversimplified description of fecundability estimates for Hutterite and Taiwanese women in the 1950s and 1960s. Two professionals contributed to the making of these data. CONCLUSIONS: The chart was fabricated and exaggerates the effect of age on the likelihood of conception. At least two professionals are responsible for the fabrication. CONTRIBUTION: This paper describes a case of misinformation about demographers' research results. It issues a warning against misuse of demographic knowledge in medical, commercial, educational, and political contexts.
In the early 2010s, Japanese society recognized and experienced a panic about increasing infertility and people's lack of knowledge about human reproduction. This paper focuses on several graphs that misrepresented or distorted scientific findings that were used in the campaign related to this panic and explores (1) how the graphs were made, used, and authorized, and (2) how they contributed to changes in discourses and policies. Findings are the following: (1) The graphs were made in the field of obstetrics, gynecology, and reproductive medicine by questionable methods, including falsifying, trimming, and misunderstanding of data. (2) Researchers in the field of fertility study relied on secondary and tertiary sources thus ignoring and compounding errors. (3) Such inauthentic research was approved and politically mobilized by professional organizations, rather than being penalized or criticized. (4) Discourse based on such unscientific knowledge may have encouraged a pronatalist policy of promoting early marriage and education about human fertility and life planning, targeted at teenage girls.
This paper reports the results of a literature review on "An Estimate of the Natural Fecundability Ratio Curve" by Bendel and Hua (1978, Social Biology 25). The estimation of this work was the origin of a falsified chart on women's age-fertility profile that was featured in a high school health education material published in 2015 by the government of Japan. The author searched citation databases and collected 23 works citing the study. A review of the 23 works showed that biases and unreliability of the Bendel-Hua estimation had been pointed repeatedly. The results imply that the chart would be inappropriate for educational use, even if it were not falsified. Both the Japanese government and academics are responsible for the inappropriate chart being used without a comprehensive literature review to insure the reliability of scientific knowledge.
"Cluster" is a term characterizing Japan's response to the outbreak of the novel coronavirus disease (COVID-19) in early 2020. Its usage is often confusing considering its multiple meanings. This study examined relevant literature, including government documents and media news, to explore the usage of the term between February 2020 and January 2021. The results show that the government and experts started using the term with three connotations in late February and early March 2020: (A) large-scale infection caused by one infector (super-spreading), (B) a chain of infection that can potentially expand, and (C) large-scale infection caused at a place or an event (group infection) regardless of the number of infectors. The use of the term with meaning A has since disappeared, while meanings B and C survived. The active surveillance system has consistently used meaning B. Meanwhile, local governments have used meaning C since early June 2020 with the concrete criterion that five or more cases should be involved, after some discrepancy in the earlier period. The central government once adopted the same usage, but subsequently showed a discrepancy by using meanings B and C interchangeably. Moreover, it expanded meaning C to include small-scale group infections with four or fewer cases (C'). This change in the usage of the term reflects a latent change in the strategy of the government and its advisory experts. Focusing on defense against super-spreaders as their primary efforts to curb the spread of infection, they used the term “cluster” to connote super-spreaders in meaning A in the early stages of COVID-19. However, during the prolonged COVID-19 pandemic, they implicitly shifted their focus to chains of small-scale infections. In order to determine the risks of infection of daily activities (eating and drinking in particular), they collected case reports of small-scale infections that they referred to as "cluster" in meaning C'. Therefore, "cluster" no longer represented the threat itself, but rather denoted a framework to determine cases representing activities with a certain level of risk that would not cause large-scale infection but could contribute to the spread of COVID-19 in the aggregate through several small-scale infections.
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