NY連銀総裁を退任するウィリアム・ダドリーが、同連銀のブログで、経済学者と法律家の考え方の違いについて語っている(H/T Mostly Economics)。

Q: Lawyers sometimes refer to ‘thinking like a lawyer.’ How would you describe what it means to ‘think like an economist?’
The classic joke is that economists are ‘on the one hand…on the other hand.’ Lawyers are advocates for a given point of view and prosecute under a well-defined set of rules of law. I think of lawyers as advocates and economists as almost like a justice balance—where they’re trying to weigh the evidence very carefully to see where the preponderance of the evidence lies.
So economists may be a little bit more open-minded to the facts—not to say that lawyers aren’t, but a lawyer’s job is to do something, to advocate a position, to protect a positon. So they’re starting with a very strong a priori view. I think economists start with a priori views, in the form of a hypothesis, but if the evidence is inconsistent then they start to change the theory and hypothesis, as opposed to arguing that the evidence is obviously not applicable.


一方、ノルウェー銀行のこちらの論文(WP)*1では、中銀と最高裁の共通性について語られている(H/T Mostly Economics経由のVoxEU記事)。

Institutions such as the central bank and the supreme court make important decisions for society. They exercise power in and over society. In a liberal democracy such as Norway, it goes without saying that this exercise of power must be accounted for. There are a number of reasons for this:

  • A decision needs to be explained to those affected. A judgement impacts directly on the parties to the case. Rulings on both criminal and civil cases can have far-reaching consequences for those directly involved. The central bank’s interest rate decisions have economic consequences and can affect many people’s lives.
  • Institutions also prepare minutes as a record of why they reached a decision, as similar cases may arise in the future. For the supreme court, key factors here include the normative effect of its judgements and the fundamental principle of equality under the law. For the central bank, they include consistency in economic thinking and economic decisions.
  • Decisions influence expectations. An interest rate decision today, and the justifications given for it, will affect expectations of future interest rates. A case will often only be heard by the supreme court if it concerns a matter of principle. The court’s judgements have a normative effect – they set a precedent. The precedent established by the court is then to be applied in other cases where similar legal questions arise.
  • To some extent, both the supreme court and the central bank compete with, and potentially interfere with, the political decisions of the country’s government and parliament. Supreme court judgements have a legislative effect, and the court plays an important role in providing checks and balances for the executive and legislative branches. The central bank’s interest rate decisions can be important for the economic policy pursued by the country’s government and parliament. Thus, the decisions of both the supreme court and the central bank have political ramifications. This argues in favour of transparent, complete, high-quality justifications for these decisions.

The justifications for a decision need to specify the premises, analyses, assessments and conclusion. The justifications for a decision can be written in different ways according to its purpose. Where a decision concerns an individual, it should if possible be explained in a way that person can understand. But if a decision is to establish a precedent, it is important for it to be written in such a way that its normative intention is clear. The justifications for an interest rate decision should be formulated in such a way that markets form the right interest rate expectations. At the same time, democratic considerations mean that they must be written in a way that is accessible for an informed public. If the justifications are intended exclusively for the institution’s internal memory, however, they can most effectively be written in the institution’s own technical language. These various factors need to be carefully weighed up when the justifications for a decision are recorded.

  • 決定はその影響を受ける人々に対して説明される必要がある。判断は対象の主体に直接的な影響を与える。刑事・民事裁判いずれの判決も、直接の当事者にとって大きな影響がある。中銀の金利に関する決定は経済的影響をもたらし、多くの人々の生活に影響する。
  • 組織は、なぜその決定に到達したかの記録として、議事録も用意する。同様の事例が将来生じるかもしれないからである。最高裁では、そこに記すべき重要な要因として、判決の規範的な影響と、法の下の平等という基本原則がある。中銀ではそれは、経済的思考と経済的決定の一貫性である。
  • 決定は予想に影響する。今日の金利の決定、およびその理由説明は、将来の金利予想に影響する。原則問題については、最高裁だけで審議されることが多く、最高裁の判断は規範的な意味を持つ――それが判例となるのである。最高裁で確立した判例は、同様の法律問題が生じた時、他の事例にも適用される。
  • 最高裁も中銀も、国の政府ならびに議会の政治的な決定とある程度競合し、かつ、潜在的に干渉する。最高裁の判断には法的な効力があり、行政ならびに立法機関のチェックアンドバランスにおいて最高裁は重要な役割を果たす。中銀の金利に関する決定は、国の政府ならびに議会が追求する経済政策にとって重要である。従って、最高裁と中銀の決定はいずれも、政治的な派生的影響を有する。このことは、そうした決定について透明、完全、かつ質の高い理由説明をすべき理由となる。


*1:タイトルは「Criteria for “good” justifications」で、著者は同銀のJan F. QvigstadとTore Schei。