None of the examples have targeted NGDP, which is what Sumner needs to be true to have supporting evidence.
I think my examples do constitute supporting evidence of some kind. Yes, it would be good to have examples of countries specifically targeting NGDP, to prevent spurious correlations or Lucas critique problems. But even so, Iceland and to a lesser extent, Poland—and, to be fair, the UK—specifically accepted a rise in inflation in order to sustain demand—it wasn’t a simple case of exogenously strong RGDP growth. (I think this might also apply to Australia, actually. Their institutional framework would certainly allow for that.) This makes the evidence quite credible, although it’s not perfect by any means.
Also, Sumner was not at all the first economist to care about NGDP as a possible target. He is a prominent popularizer, but James Meade and Bennett McCallum had proposed it first.
Your example of the “benefits of hoarding” doesn’t address the very specific problems with hoarding the unit of account for all prices in the economy, when prices are hard to adjust. Yes, money has a real option value, so money hoarding might signal some kind of uncertainty. However, you have not made the case that this “signaling” has any positive effects, especially when the operation of the price system is clearly impaired. By analogy, if peanuts were the unit of account and medium of exchange, then widespread hoarding of peanuts might signal uncertainty about the next harvest. But it would still cause a recession, and it wouldn’t actually cause the relative price of peanuts to rise (or rise much at any rate), which is what might incent additional supply.
Moreover, in practice, an uncertain agent can attain most (if not all) of the benefit of hoarding money by holding some other kind of asset, such as low-risk bonds, gold or whatever the case may be. It’s not at all clear that hoarding money specifically provides any additional benefit, or that such incremental benefits could be sustained without inflicting greater costs on other agents.
I think my examples do constitute supporting evidence of some kind. Yes, it would be good to have examples of countries specifically targeting NGDP, to prevent spurious correlations or Lucas critique problems. But even so, Iceland and to a lesser extent, Poland—and, to be fair, the UK—specifically accepted a rise in inflation in order to sustain demand—it wasn’t a simple case of exogenously strong RGDP growth. (I think this might also apply to Australia, actually. Their institutional framework would certainly allow for that.) This makes the evidence quite credible, although it’s not perfect by any means.
Also, Sumner was not at all the first economist to care about NGDP as a possible target. He is a prominent popularizer, but James Meade and Bennett McCallum had proposed it first.
Your example of the “benefits of hoarding” doesn’t address the very specific problems with hoarding the unit of account for all prices in the economy, when prices are hard to adjust. Yes, money has a real option value, so money hoarding might signal some kind of uncertainty. However, you have not made the case that this “signaling” has any positive effects, especially when the operation of the price system is clearly impaired. By analogy, if peanuts were the unit of account and medium of exchange, then widespread hoarding of peanuts might signal uncertainty about the next harvest. But it would still cause a recession, and it wouldn’t actually cause the relative price of peanuts to rise (or rise much at any rate), which is what might incent additional supply.
Moreover, in practice, an uncertain agent can attain most (if not all) of the benefit of hoarding money by holding some other kind of asset, such as low-risk bonds, gold or whatever the case may be. It’s not at all clear that hoarding money specifically provides any additional benefit, or that such incremental benefits could be sustained without inflicting greater costs on other agents.