About every second paper in JPE/QJE is about Norwegian data. What do we learn from this? Is the purpose of economics as a field to make policy recommendations valid exclusively in Norway?Silly you with your external validity concerns. If it works for a homogeneous country of 5M people with 2nd highest gdp per capita in the world and a sovereign wealth fund of over $1T and 1.3% of worldwide assets...it must work everywhere. It's just like how research on Sumo wrestler corruption applies to all corruption contexts...
Magne and Bertil beg to disagree with you, while preparing the next issue of JPE that will feature two articles by Magne and two by Bertil...