Thank you for the reply. Indeed, I was referring to the studies engaging with butter-margarine substitution. However, I think it definitely needs emphasising just how weak those studies are and thus that they cannot be trusted to make any policy decisions. Additionally, while relevant, I would not want to use Auer and Papies (2020) as a basis for policy decisions either, as it is quite unclear how comparable those estimates are due to them pooling across a wide range of markets potentially quite different to this one (is the degree of product differentiation the same? groceries could be different to pharmaceuticals or durables). Finally, there is also the issue the papers they synthesise using instruments might not use good ones, but I do not have the time to check that.
Thank you for the reply. Indeed, I was referring to the studies engaging with butter-margarine substitution. However, I think it definitely needs emphasising just how weak those studies are and thus that they cannot be trusted to make any policy decisions. Additionally, while relevant, I would not want to use Auer and Papies (2020) as a basis for policy decisions either, as it is quite unclear how comparable those estimates are due to them pooling across a wide range of markets potentially quite different to this one (is the degree of product differentiation the same? groceries could be different to pharmaceuticals or durables). Finally, there is also the issue the papers they synthesise using instruments might not use good ones, but I do not have the time to check that.