Optimal tax the optimum. Stipulating this condition results in the following formula for the optimal top tax rate, if incomes are Pareto distributed: formula_1 where: Empirical estimation of the parameters of this equation suggests that the revenue-maximising top tax rate is between approximately 50% and 80%, although this estimate neglects long-run behavioural responses, which would imply higher elasticities and a lower optimal tax rate. Saez's analysis can also be generalised to tax rates other than the top rate. In the late 1970s, Arthur Laffer developed the Laffer curve, which demonstrates that there are two effects of changing tax rates: an arithmetic effect—if
Notional Defined Contributions pension system the pension is based on history of lifetime earnings and is much more heavily influenced by misreporting of one’s income. In Poland NDC pension scheme was introduced in 1996. The country faced serious fiscal challenges with rate of contribution into the pension system having reached 45% of gross wage. The system was implemented in 1999 after long political discussion about its various aspects and was meant as means of both reducing the future pension debt and motivating workers to prolong their careers. Notional Defined Contributions The term Notional Defined Contributions or Non-financial Defined Contributions or NDC refers to