Now I have not read the paper, but what the articles quotes seems to make some flawed assumptions, that you can measure the difference of effect of the flat tax

Now I have not read the paper, but what the articles quotes seems to make some flawed assumptions, that you can measure the difference of effect of the flat tax era versus post flat tax era in these countries, is that even possible without speculation? After communism these countries where left in very dire situation, their economies where not adopted for a market based economy, everything from diversified private companies, regulatory institutions, monetary policies, relevant tax codes, functional banking system, trade policies etc. In that kind of environment it probably makes sense to introduce a flat tax, there is just too many unknowns. Initially you will probably experience a good growth because of high demand rebuilding when leaving the old system behind and of course high positivism of national sovereignty. However as time goes by and your economy progresses and your economical infrastructure gets into place, why would you expect the same, high or low, growth as the early years? Your economy is not organized the same a decade ago, classic apples to oranges comparison. Also, your national focus has probably shifted to other important areas now when you gotten the fundamentals in place. Over time, the initial assumptions changes about how things works, you can't get perfect regulatory bodies and monetary polices on the first try, so there is probably a lot of tinkering with the system as time goes by, why should the tax code be exempt from that tinkering? Why assume that the tax code was perfect on the first try but not the other policies? How do you know that the lack of economic growth is due to the tax code changes and not the changes in monetary policies? As I said in the beginning, I haven't read the paper so I can be mistaken. It probably answers a lot of these questions, but these kind of articles that quotes a few lines and then passed around on the internet as legitimate argument does not help.