Which unconventional monetary policies hold most promise?

Kudos to Biagio Bossone, Chairman of the Group of Lecce and former central banker (and circuit theorist par excellence), for his first-rate analysis (see here: part 1 and part 2) of the different types of unconventional monetary policy measures that have been implemented and proposed in the last few years!

Bossone's piece does a fantastic job of presenting the different policy proposals into six distinct categories based on their implied transmission channel and the degree of cooperation between the fiscal and monetary authorities that is required in order to implement the proposed measures.

The main take-away from the analysis is that Bossone finds the proposals that aim to boost aggregate demand via fiscal actions are the most promising. According to Bossone, the benefits of fiscal measures (with or without actions by the monetary authority) are that their effect is more direct than policy measures such as quantitative easing (which works indirectly via its impact on interest rates) or forward guidance (which works indirectly via its effect on the public's expectations on future interest rates).

In the concluding paragraph, Bossone writes,

...this result vindicates the proposed measures to expand the money supply via overt monetary financing or neo-chartalism, which aims to inject new money independently of central banks' interest-rate policies, especially if these are limited by the zero lower bound.

Reference

Bossone, B., Unconventional monetary policies revisited, Part 1 and Part 2, Vox, October 2013