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We can now answer such questions thanks to a new software tool, the Google Books Ngram Viewer, introduced in a research paper by Jean-Baptiste Michel and others (13 authors are listed, plus the Google Books Team); the paper has just been published in the journal Science, and was picked up in the New York Times. The authors have formed a corpus of over 500 billion words (360 billion in English) from over 5 million books spanning 1800-2000.
For the present purpose, an “n-gram” is just a phrase, made up of words (“1-grams”). The Ngram Viewer allows users to track the frequency of any given word or phrase. The count in a given year is normalized by the total number of words in the corpus for that year. This total rises over time; Michel and colleagues estimate that there were about 1 million words in English in 2000, but barely half that number in 1900. (And most of that growth was in the latter half of the 20th century.)
So we have a new window on the prominence of ideas in the writings of their time. The paper by Michel et al., provides a number of interesting applications, and there are doubtless many more to come.
This post uses the new tool to see how some of the main ideas related to economic development have figured in the literature over the last 200 years. I will focus solely on English language literature.
Figure 1 gives time profiles for selected issues related to development. We see that “economic development” emerged as an idea around 1900. It gained usage slowly until 1950, at which time there was a sharp increase in pace; indeed, its share of all words increased by a factor of five in the 20 years after 1950, though falling back somewhat after 1970. The term “Third World” appeared around 1960, ballooned in the next 20 years, but faded rapidly in the 1990s. “Foreign aid” was used back into the early 19th century, though not often; the term also picked up after 1950, though fading from use after 1965. (The terms “development aid” and “development assistance” compensated for some of this decline in the 1980s and ‘90s, though their frequencies were still small, and I did not include them in the graph.)
References to “famine” were common in the early 19th century but declined over time, while “migration” and “inequality” rose in prominence. “Climate change” emerged in the 1990s (“global warming” followed a similar profile, though I did not include it to reduce the clutter) as did “globalization,” which shows a very rapid rise from the late 1980s, which has no doubt continued.
“Poverty” is a more common and (clearly) much older concept. The word was becoming steadily less frequent (relative to the volume of all words) through the 18th and 19th centuries and into the 20th century up to the mid-1950s. Then the trend reversed, and markedly so in the 1960s. This peaked in the 1970s, with a decline thereafter, followed by a marked resurgence of interest starting in the mid-1980s.
| Figure 1: The evolution of some development issues in Google Books 1800-2000 |
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| Click here to see a larger version of this graph. |
The new wave of attention to poverty came alongside the greater awareness of the problems of economic development more generally. This is evident when one looks more closely at the books concerned, which one can do by opening up the period-specific data bases. The 18th century books that talked about poverty were typically referring to Europe (with only passing references to other regions). Examples include Thomas Malthus’s “An Essay on the Principle of Population” (1806) and William Dawson’s “An Inquiry into the Causes of the General Poverty and Dependence of Mankind.” (Dawson was an advocate of free trade, and a critic of Malthus.)
By contrast, the works of the late 20th century span the world, and many are about poverty in developing countries. The first to appear in the website’s window for 1987-2000 is an edited volume, “Poverty: A Persistent Global Reality,” by John Dixon and David Macarov, published in 1998. A quick perusal of the volumes in this window suggests that roughly half are on developing countries. (America is prominent in the late 20th century literature on poverty in developed countries.)
Strikingly, references to “pollution” look like a smaller but stretched version of the series tracking “poverty.” The two go hand-in-hand, with both showing an upsurge of interest in the 1960s, a decline thereafter, but a re-bound in the 1990s.
Figure 2 drills down further to track various economic concepts. “Economics” appeared as a term in the late 19th century (though “political economy” was used similarly prior to that). “Taxation” was the most frequently mentioned topic amongst those selected in all years up to 1970, when macroeconomic issues (“fiscal”, “monetary” and later “deficit”) started to get more attention. (It may be that taxation started to become an accepted fact of life after the Second World War.)
Prior to the Great Depression, the word “fiscal” was more common than “monetary.” The latter word had an upsurge in the wake of the Depression, and again in the 1980s and ‘90s. Mentions of “deficit” rose over time, peaking in 1990. Mentions of the “exchange rate” ballooned in the 1970s and ‘80s, but subsided from the mid 1990s. The word “macroeconomic” followed a similar course. “International trade” has had a more steady following, with interest peaking in the 1990s; the previous high point was at the end of the Second World War.
| Figure 2: Some economic ideas in Google Books |
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| Click here to see a larger version of this graph. |
The phrase “economic growth” appeared on the scene around 1950. It is notable how much interest in inequality has kept up with interest in economic growth. There is no sign here that concern about inequality has abated with the rising prominence of economic growth as a topic in the literature.
The 20th century saw a huge expansion in mentions of education and schooling in the literature (Figure 3). The frequency of mentions of “health” stayed fairly steady until about 1970, but has risen sharply since then, doubling in 30 years. In the late 19th century, “disease” was used more frequently than “health” or “education."
| Figure 3: Elements of human development in Google Books |
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| Click here to see a larger version of this graph. |
The frequencies of various infectious diseases are plotted in Figure 4. We see the large swings in the frequencies of most diseases, with generally falling incidence since the Second World War. The exceptions are hepatitis and HIV, which became more frequently mentioned from about 1980 (though it was only in the 1960s that serum hepatitis was identified) and with a sharp rise in the 1990s for HIV.
Finally, let’s looks at references to specific countries. Figure 5 plots my selections. What is most striking here is the convergence. England and France (which started well ahead of the rest) are referred to less often over time. “America” saw generally higher frequencies over time. (The two World Wars stand out, with references to “America” peaking after those to “Germany.”) India and China have become steadily more prominent.
| Figure 4: Infectious diseases in Google Books |
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| Click here to see a larger version of this graph. |
| Figure 5: Countries in Google Books |
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| Click here to see a larger version of this graph. |
Jean-Baptiste Michel and his collaborators, including Google Books, have provided us with a fascinating new tool for exploring the history of ideas. I have only scratched the surface here. But be warned, it is also hard to stop playing with the Ngram Viewer once you get started!
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Also read, 'Awareness of poverty over three centuries' on VoxEU.org and working paper 'The two poverty enlightenments: historical insights from digitized books spanning three centuries '.
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