Augus Deaton攞諾貝爾 其他經濟學者點講？

2015年諾貝爾經濟學獎由 Princeton 頂級學者Angus Deaton 奪得，以表揚其在量度消費、貧窮及福利上的貢獻。有關其學術貢獻，我在此不班門弄斧，故打算轉介各位讀者看看其他經濟學者，對Deaton的學術貢獻的評價，並看看這個獎是否名符其實。

首先，當然要看Tyler Cowen的評價。在結果公佈後，Cowen馬上認定這是「Brilliant Selection」。他認為今次諾獎是對實證經濟學研究的肯定，並指出Deaton為一位真正瞭解經濟增長意義、現代化的好處及政治經濟分析重要性的學者。

Think of Deaton as an economist who looks more closely at what poor households consume to get a better sense of their living standards and possible paths for economic development. He truly, deeply understands the implications of economic growth, the benefits of modernity, and political economy. 

曾為Deaton學生的著名發展經濟學者Dani Rodrik就寫道:

I took my first econometrics course with Deaton. Learned more there than in all others combined.

— Dani Rodrik (@rodrikdani) October 12, 2015

專研宏觀經濟及Happynomics的學者Justin Wolfers就對Deaton奪獎興奮不已，在其NYT對Deaton貢獻簡介的文章中寫道，Deaton一生致力為了解貧窮問題而努力。其研究集中在理解貧窮國家所面對的問題，而其方法與以往的扶貧學者有所不同。以往的扶貧專家往往會負起貧窮醫生的角色，當發展中國家了解經濟出現結構性問題，這些專家就被邀請到該家「診症」，雖然每個國家的情況都不同，但往往扶貧專家都會下同一樣的「藥方」，例如推動基建、推行工業政策、增加國民儲蓄等宏觀經濟政策。 但Wolfers指出，Deaton的研究帶領下，新一代的發展經濟學者變得更重視真正了解貧窮人士的生活，及開始分析經濟制度的細節如何影響一國的發展，而微觀行為數據成為研究重點，這對扶貧帶來相當正面的影響。

Today, development economics is a far more interesting and nuanced field, with practitioners focused on understanding the lives of the poor, and in uncovering the subtle ways in which immature economic institutions hinder their development. Rather than studying a few dozen countries, modern development economists are likely to pore over data describing the economic lives of thousands of families within each country.

而Wolfers老婆，另一著名學者Betsy Stevenson亦有同樣看法:

Deaton is a hardcore empiricist who has taken data on subjective well-being seriously & helped show what we can learn from it — Betsey Stevenson (@BetseyStevenson) October 12, 2015

Marginal Revolution 另一位博客Alex Tabarrok教授，在其簡介Deaton貢獻的文章，就強調Deaton在量度貧窮的研究上的重要貢獻。其中Deaton與World Bank合作研究計算全球各國貧窮問題，就是現是世銀的貧窮人口統計的重要基石。

Tabarrok指出，量度不同國家的生活水平並非易事，因為雖然不少商品可以在自由貿易下，在環球市場訂定合理的市價，但非貿易商品甚至消費服務，在各國就會有不同的定價。例如Balassa-Samuelson effect就推斷在較貧窮的國家，相同服務會較富國便宜，因為工人的薪金會相對低一點，而產品價格又未有得到適當的環球市場調節。在這個前提下，單以市場匯率計算窮國人民的消費及生活水平，大有機會出現系統性低估。Deaton的貢獻在於與世銀合作，研究解決這個各國服務商品價格可比性的問題，其中一個結論是利用家庭調查（household survey）中的消費總額數字，除以消費總量數字，計算出服務/商品的Unit Value，作比較價格的輔助指標。

Deaton, working especially with the World Bank, helped to construct price indices for all countries that measure goods and services and he showed how to use these to make theoretically appropriate comparisons of welfare. Deaton’s presidential address to the American Economic Association in 2010 covers many of these issues.

行為經濟學學者兼法律教授Cass R Sunstein就在Bloomberg Views上，講及Deaton在鼓勵學界採用收入以外的指標（如正負面情緒、健康情況等），來作為量度生活水平的方法，並特別介紹Deaton與另一位諾獎得主Daniel Kahneman的2010年發表的研究。兩位大師的研究結果顯示，美國人收入與開心程度的正向關係，當其年薪達到七萬五美元就會消失，就是說錢買快樂的能力似有其上限。

但其實研究結果有更深入的含意，就是量度Well-being的實證問題。研究中「快樂」的意思，只為受訪者在回答有關「短期的正面情緒」問題時答案，但當受訪者評估整體生活滿意度（life satisfation）, 收入愈高，life satisfation仍會不停升高，不會見頂。即是賺100萬同七萬五的人，短期的正面情緒相近，但life satisfation相距可以甚遠。

Sunstein認為這個研究有相當實際的政策貢獻，例如政府可以考慮對年薪七萬五以下的人士，提供更多經濟支援。

Deaton has demonstrated that if the goal is to improve people’s lives, we ought to be focusing most aggressively on helping people who earn less than $75,000 — and also on helping caregivers, parents of young children, smokers, and people with chronic illnesses. At the same time, the government might want to direct fewer resources toward programs that disproportionately benefit those above that threshold — on the simple grounds that the money is likely to generate a lower return.

Hover Institutions的學者David Handrson就將焦點，放在Deaton兩年前出版的着作《The Great Escape》內，批評富有國家政府以直接資金援助貧國，是愈幫愈忙的行為。

Deaton在書中指，這類政府對政府的直接經濟支援，無法真正改變貧國內大量制度問題，亦無法為民眾帶來發展空間及經濟誘因，反而可能為腐敗的貧國政府，提供更多資源，到頭來經濟破壞更大。

What’s his problem with the hydraulic approach? It ignores the fact that to really help those countries, we need them to get their institutions right, or, at least, roughly right. Deaton writes: “Innovators need to be free from the risk of expropriation, functioning law courts are needed to settle disputes and protect patents, and tax rates cannot be too high. When all of these conditions come together— as they have in the United States for a century and a half— we get sustained economic growth and higher living standards.”

Government-to-government foreign aid does nothing to help these things happen and, indeed, almost certainly makes governance in those countries worse.

著名發展經濟學學者Paul Romer，就形容Deaton為「緊慎的樂觀主義者」（Careful Optimist）。他亦引述Deaton的《The Great Escape》，指Deaton的研究明確反映出，現代人的生活較百多年前，祖父一代已大有改進。不單平均收入、人均壽命等得到極顯著改善，其實暴力行為亦有大幅減少，民主政制亦更為常見，不同社群互相仇恨的情況亦有所減少。Deaton就是鼓勵大眾以緊慎的態度，同時配上多角度多方向觀察，來認真審視何謂貧窮。

Deaton’s work, backed by the recognition it has now received, means that the biggest fact about life on earth can no longer be disputed or dismissed:

Life has been getting better, and getting better at a pace that is inc

最後，就介紹大家睇徐教授在蕭生節目上，分享半年前曾與Deaton同台食飯，及Deaton分享的一個故事: