Why the history of economic growth should be all about recessions

“THROUGHOUT history, poverty is the normal condition of man,” wrote Robert Heinlein, a science-fiction writer. Until the 18th century, global GDP per person was stuck between $725 and $1,100, around the same income level as the World Bank’s current poverty line of $1.90 a day. But global income levels per person have since accelerated, from around $1,100 in 1800 to $3,600 in 1950, and over $10,000 today.

為何經濟增長史的一切端由應是衰退

“縱觀歷史，貧窮是人類社會的常態”，科幻作家羅伯特·海因萊因寫道。直到18世紀，全球人均GDP一直停留在725至1100美金之間，這個收入水平大約與世界銀行劃定的貧困線持平，每天1.9美金。但從那時起，全球人均收入水平開始加速增長。從1800年的1100美金到1950年的3600美金，現在已經超過10000美金。

Economists have long tried to explain this sudden surge in output. Most theories have focused on the factors driving long-term economic growth such as the quantity and productivity of labour and capital. But a new paper* takes a different tack: faster growth is not due to bigger booms, but to less shrinking in recessions. Stephen Broadberry of Oxford University and John Wallis of the University of Maryland have taken data for 18 countries in Europe and the New World, some from as far back as the 13th century. To their surprise, they found that growth during years of economic expansion has fallen in the recent era—from 3.88% between 1820 and 1870 to 3.06% since 1950—even though average growth across all years in those two periods increased from 1.4% to 2.55%.

長久以來，經濟學家試圖解釋這一產出激增。大多數理論都聚焦于驅動長期經濟增長的因素，如勞動力數量和生產力以及資本。但是一篇新論文采取了不同的方法進行探究：增長加速并不是源于于繁榮期的更大發展，而是因為衰退期的收縮程度減弱。牛津大學的史蒂芬·布勞德伯利和馬里蘭大學的約翰·瓦利斯收集了歐洲和美洲的18個國家的數據，有些甚至追溯到13世紀。令他們驚訝的是，他們發現經濟擴張年份的增長率在近期反而是下降的，從1820年至1870年的3.88%下降到1950年至今的3.06%，盡管這兩個時期里所有年份的平均增長率從1.4%上升到了2.55%。