"A preponderance of evidence nonetheless suggests that forward guidance and quantitative easing succeeded in lowering long-term interest rates. Studies using micro data have documented tangible effects of quantitative easing on firms and financial intermediaries. Macro models suggest that the interest rate reductions are likely to have had a meaningful impact. The adverse side effects appear to have been mild, and are dwarfed by the costs of the more protracted recession in the United States that likely would have occurred in the absence of the unconventional policies. The benefits of unconventional policy therefore probably outweighed the costs.
"Some questions are not entirely settled. First, the persistence of the effects on interest rates remains unclear. Second, disentangling the effects of quantitative easing from those of forward guidance is difficult. Third, the effects of these policies may have been in part a function of turbulent financial conditions, or may have diminished over time as the novelty wore off."