**Andrew Gelman**: *China Air Pollution Regression Discontinuity Update* https://statmodeling.stat.columbia.edu/2018/08/02/38160/: 'If fourth-degree polynomials had never been invented, researchers could look at the above graph with just the scatterplot and draw their own conclusions, with no p-values to mislead them. The trouble is that, for many purposes, we do need advanced methods—looking at scatterplots and time series is not always enough—hence we need to get into the details and explain why certain methods such as regression discontinuity with high-degree polynomials don’t work as advertised...

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#noted #2020-01-28
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