Newsletter No. 434

10 No. 434, 19.3.2014 Why did you switch to economics in graduate school after obtaining a first degree in engineering? Motivated by poverty, most people of my generation studied extremely hard when China resumed its college entrance examination system. I did fine in my engineering major for the first degree, but I did not find it very interesting. By contrast, I was very sensitive to ever-changing social phenomena. So upon graduation I enrolled in an MBA programme, and eventually went to Canada for economic studies with help from a famous economist Prof. Gregory C. Chow . Why, among all the fields of economics, are you attracted to the analysis of social issues such as crime, fertility, marriage, education, gender bias and old-age support? I was inspired by a monograph on family economics by Gary Becker who was awarded a Nobel Prize for analysing social issues from an economic approach. It made me realize how powerful economics can be in explaining human behaviour. It is a general misunderstanding that economics only teaches students to make money. Economics is the study of how people make decisions on how best to satisfy their needs with limited resources. In fact, consciously or unconsciously, we all use economics in everyday decision-making even without knowing any economic theory. How does economics explain human behaviour? Take the decision to have children as an example. In developing countries, raising children is an insurance against some of the perils of old age. But in countries with developed capital markets, potential filial support is not the main reason for making the decision. In the latter case, the economic analysis views having a child as a ‘durable consumption’; it assumes and discovers that child-rearing increases parental happiness. We certainly do not deny the importance of social and psychological factors, and so forth, or that children could be the product of love. We just do away with rhetoric and use as much as mathematical language or graphics to distil an issue down to its economic essence. Tell us something about your recent election as a Fellow of the Econometric Society. Established in 1930, the Econometric Society is the most prestigious international society for the advancement 你本唸工程，為何攻讀碩士學位時轉修經濟？ 因為貧窮，使得我這批人在高考恢復後特別勤奮。我在大 學讀工科時成績不錯，但發現自己對工程興趣並不特別 大，反而對環境和社會現象的變化很敏感。於是先讀工商 管理碩士，繼而因緣際會在著名經濟學家 鄒至莊 教授幫助 下，轉到加拿大讀經濟。 為何鍾情犯罪、生育、婚姻、教育、性別偏見及養老等 社會議題涉及的經濟問題？ 諾貝爾經濟學獎得主 加里．貝克爾 一本家庭經濟學的著作 啟發了我，讓我意識到經濟學在解釋人類行為方面驚人的 力量。很多人以為經濟學只教學生賺錢，那是個誤解。經 濟學說的是為達到某個目標，怎樣在眾多約束之下優化選 擇。日常大家不管懂不懂經濟學理論，都在無形運用經濟 學，只是沒有意識到。 能否舉個簡單例子，說明怎樣以經濟學解釋人的行為？ 就說選擇要不要孩子的問題吧。在發展中國家，養兒是為 了防老，但在發達社會要保障退休生活有很多方法，那已 經不是主因。經濟學把生育小孩視作擁有「耐用消費品」， 假定及推算出在發達社會，孩子會增加父母的幸福指數。 當然這不是說否認社會學、心理學等作用，也不否認孩子 是愛情結晶，經濟學只是褪去感性的美麗修辭，分析行為 的經濟實質，盡量以數學或圖像表達。 最近獲計量經濟學會推選為院士，請介紹一下背景。 計量經濟學會成立於1930年，是世界最富盛譽的經濟學 學術組織。我是本年度亞洲區內唯一當選的學者。目前為 止，中國還有三位學者曾獲此榮銜，分別在清華、北大和 上海交大。我是第四個，而且是唯一「土生土長」的─我 在加拿大工作了三年半就來了中大，那時還是講師，一教 二十年。今天這份成就雖是個人努力的結果，但也和中大 的學術環境密不可分。 這次當選對於你的教學或研究有甚麼意義？ 鼓勵我調整目標。教授在資歷較淺時往往從個人角度出 發，追求多產、多發表文章。院士是一種榮譽和認可，此後 的追求就應提升學術及社會層次。我會集中更多精力於一 些更基礎的研究。最近開展的一些項目也圍繞貧窮、社會 不平等、留守兒童、社會流動等社會問題。 是甚麼驅動你在中大一教二十年？ 對學術的熱情是最大動力。經濟學和商業息息相關，外界 有很多誘惑向我們招手，也有其他大學的招攬，但我最後 還是選擇留下來。我一直很喜歡中大的研究環境。這裏自 然環境也優美，空氣清新，令人留戀。 這些年你不時出任政府的政策顧問，可否分享箇中 經驗？ 這方面我有點「愛恨交纏」。在政府服務過數個委員會， 包括前策略發展委員會，也擔任過政府部門顧問。他們有 時會採納我的建議，例如討論人口政策時放棄用「香港最 優人口數量」這個概念。不過有時也難免氣餒，我曾提議 仿效美國普遍做法，對社會項目效益進行科學評估，但他 們至今仍未跟進。 of economic theory and application. Among the newly elected Fellows, I am the only scholar from Asia. There are three Chinese scholars previously elected, and they are now teaching respectively at Tsinghua University, Peking University and Shanghai Jiao Tong University. I am the fourth, and the only ‘home-grown’ scholar. I had only worked for three and a half years in Canada before joining CUHK as a lecturer. Twenty years have gone by. I have worked hard for my achievements which owe much to the academic environment of CUHK. What impact would the fellowship have on your teaching and research? It encourages me to aspire to higher goals. Junior professors tend to shape a productive career path by focusing on publication. Having obtained the honour and recognition bestowed by the fellowship, I am at liberty to advance my pursuit in academic and social dimensions. I shall focus more on fundamental research. Recently I have also undertaken some projects on poverty, social inequalities, left-behind children and social mobility. What keeps you teaching at CUHK for 20 years? The motivation comes mainly from the passion for academic pursuits. As economists, we are closer to the business world so there are always some outside opportunities in the industry. I have also been approached by and indeed received offers from other universities, but I chose to stay in the end. I enjoy the excellent research environment at CUHK. The natural beauty and good air quality are also among the reasons I like the University. Over the years you have provided consulting services and advice to governmental agencies. Can you share the experience with us? I have some mixed feelings about that. I have served in some committees in the government, including then the Commission on Strategic Development, or as a consultant for government agencies. Sometimes they took my advice. For example, when discussing population policy, they gave up the concept of an optimal population size in Hong Kong. But there were also times when nothing was done. On one occasion, I suggested to conduct scientific effectiveness evaluation of social projects as commonly practised in the US, but so far they still have not followed up on that. 張俊森教授 • 偉倫經濟學講座教授 • 經濟學系系主任 • 計量經濟學會院士 Prof. Zhang Junsen • Wei Lun Professor of Economics • Chairman, Department of Economics • Fellow of the Econometric Society