Very often these needs are defined without consultation of other institutions already collecting data, or there is consultation, but minor differences concerning the data needs used to collect different sets of data persist. What would be better would be to try to overcome these differences and to collect a single set.
Other things equal, a higher real equilibrium interest rate implies that monetary policy interest rates also have to move to a higher level, consistent with the new equilibrium. So, a major issue is to determine the trend rate of productivity growth.