【英文】经合组织报告：全球经济展望报告：中国经济今年预计增长8.5%（221页）

The pandemic affected all countries’ GDP in 2020 but with some noticeable disparities (Figure 1.2,  Panel A), including sizeable differences across countries in the relative declines of nominal and real GDP,  and implicitly in the GDP deflator. Cross-country variation in observed GDP outcomes arises from many  different sources, including the timing and severity of the pandemic and the associated policy responses,  the different sectoral mix of economic activities in each country, and differences in statistical procedures.  This box explores the extent to which one particular statistical difference – the treatment of non-market  services – accounts for some of the variation in real GDP growth across countries during 2020. While  marked differences can be seen in the contributions from non-market services across countries, these are  generally small relative to the overall changes in GDP and make little difference to the relative GDP  declines across countries. These issues will remain pertinent in 2021, given the renewed shutdowns and  subsequent reopenings that are occurring.Estimating the volume of output in the health and education sectors is challenging as output is often  supplied without charge or at prices that are not economically significant. 

Different conventions exist across  national statistical institutes (NSIs) to compute the volume of non-market services: using deflated  measures of input values, or direct volume measures of either inputs (such as the number of employees  or hours worked) or outputs (such as the number of students or number of patients treated) (OECD, 2020a).  The COVID-19 pandemic has added to these longstanding issues, with both sectors heavily affected by  restrictions. For instance, workers may be paid as before during shutdowns but provide a reduced volume  of services. This results in differences between approaches that deflate input costs (such as the wage bill,  which did not change) or measure the volume of activities via inputs (such as the number of teachers,  which did not change) or outputs (such as the number of students coming to school, which did change).  Services may also be delivered in different ways, such as the partial replacement of school-provided  education, which is included in GDP, with unpaid home schooling, which is not. Adjustments may also be  needed to capture new activities, such as the introduction and rapid expansion of test, track and trace  services, and more recently vaccinations, with associated technical issues of whether the weights given to  these new activities are appropriate. The pandemic also temporarily revamped many health services from  traditional to COVID-19-related care. All these factors may have reduced the comparability of economic  outcomes across countries.