Interview with Maureen Cropper: Environmental Economics

Catherine L. Kling and Fran Sussman have "A Conversation with Maureen Cropper" in the Annual Review of Resource Economics (October 2019, 11, pp. 1-18). As they write in the introduction: Maureen has made important contributions to several areas of environmental economics, including non-market valuation and the evaluation of environmental programs. She has also conducted pioneering studies on household transportation use and associated externalities." There also is a short (~ a dozen paragraphs) overview of some of Cropper's best-known work, I had not know that Cropper identified as a monetary economist when she was headed for graduate school. Here is her description of her early path to environmental economics:

My first formal introduction to economics was in college. I entered Bryn Mawr College in 1966. I had great professors at Bryn Mawr: Philip W. Bell, Morton Baratz, and Richard DuBoff. I learned microeconomics by reading James Meade's A Geometry of International Trade—that's how we were taught microeconomics by Philip Bell. It was really a very good grounding in economics. I got married as I graduated from college to Stephen Cropper (hence my last name), and I went to Cornell University because Stephen was admitted to the Cornell Law School. I was admitted to the Department of Economics at Cornell.

Frankly, my interests at the time were really in monetary economics, so I took several courses at the Cornell Business School, including courses in portfolio theory. My dissertation was on bank portfolio selection with stochastic deposit flows. My dissertation advisor was S.C. Tsiang. Henry Wan and T.C. Liu were also on my committee. Henry was a fantastic mentor and advisor. I would write a chapter of my dissertation and put it in his mailbox; the next day he would have it covered with comments. He was just an amazing advisor and very, very engaged. At this time, I was not doing anything in environmental economics. In fact, my first job offer was from the NYU Business School.

The reason I went into environmental economics is that I met Russ Porter in graduate school. Russ later became the father of my children. We decided that we would go on the job market together and looked for a place that would hire two economists. We wound up at the University of California, Riverside, which at the time was the birthplace of the Journal of Environmental Economics and Management (JEEM). I was on the job market in 1973, just when this journal was launched. Ralph d'Arge was the chair of the department then. Tom Crocker also taught there, and Bill Schulze and Jim Wilen were students in the department.

It was going to UC Riverside that really caused me to switch fields and go into environmental economics. It was a very important decision, although I must say it was made partly for personal reasons. It's had a huge impact on my life.

In the interview and overview, it quickly becomes apparent that Cropper has worked on an unsummarizably wide array of topics. Examples include stated preference studies to estimate the value of a statistical life, which became the basis for estimates used by the OECD and in Canada. Another study, which became the basis for EPA regulations, estimated the value of avoidint a case of chronic bronchitis through air pollution regulations. Cropper worked on whether or not to ban certain pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act, what methods to use in cleaning up Superfund sites, and whether to ban  certain uses of asbestos in under the Toxic Substances Control Act (TSCA). She worked how to use trading allowances to reduce sulfur dioxide (SO2) emissions under the Acid Rain Program.

Cropper worked on many issues involving air pollution in India. She worked on models of estimating household location choices in Baltimore and in Mumbai. The studies in Mumbai became the basis for looking at other policies: slum relocation or converting buses to compressed natural gas. She has estimated how the shapes of cities affect demand for travel, and studied cross-country data on relationships from growth to traffic fatalities. The interview touches on these topics and more. Here's a description of one such study from Cropper:

When I first got to the World Bank I realized that, in India, there hadn't been any state-of-the-art studies on the impact of air pollution on mortality. This was around 1995, the time when important cohort studies by Arden Pope and Douglas Dockery were coming out in the United States.

There is also literature looking at the impact of acute exposures to air pollution—daily time-series studies of the impact of air pollution on mortality. With the support of the Bank, I was able to get information in Delhi from air quality monitors—four years of daily data, although monitoring was not done every day. I was also able to obtain data on deaths by cause and age. I worked with Nathalie Simon and Anna Alberini to carry out a daily time-series study of the impact of air pollution on mortality. ...

We had a hard time getting the study published in an epidemiological journal because economists write up their results differently than epidemiologists. But we did document significant effects of particulate matter on mortality. And, it was important to do something early on and convince people in India that this sort of work could be done. (There have been many subsequent studies.) It is also interesting that the results we obtained in Delhi were similar to results obtained in other time-series studies in the United States.

When those at the EPA or the World Bank or the National Academy of Sciences were setting up an advisory committee or a consensus panel to produce a report or an evaluation, Cropper's name was perpetually on the short list. Her memory of one such experience gives a sense of why she has been in such high demand:

I learned so much in my time serving on the EPA Science Advisory Board. I actually began there in the 1990s when the retrospective analysis of the Clean Air Act—the first Section 812 study—was being written. Dick Schmalensee was the head of that committee. I actually chaired the review of the first prospective 812 study of the benefits and costs of the 1990 Clean Air Act Amendments.

I also preceded you, Cathy, as the head of the Environmental Economics Advisory Committee at EPA. I learned a lot being on these EPA committees. In terms of the 812 studies, you've got a subcommittee that's dealing with the health impacts: epidemiologists and toxicologists. You have air quality modelers and people who are exposure measurement experts. And of course, you also have economists. It's a fantastic opportunity to be exposed to all parts of the analysis. If you are concerned about air pollution policy, which is what I've worked on the most, you need to get the perspective of all of these different disciplines. 

I was also interested in Cropper's comments on how, in environmental economics, theoretical research has diminished and empirical work has become more prominent. My sense is that this is broadly true for many fields of economics. Cropper says 

I think quasi-experimental econometrics are one of the things that graduate students really do learn nowadays. Graduate students are also learning structural approaches. If you want to estimate the welfare impacts of corporate average fuel economy (CAFE) standards on the new car market, you've got to use a structural model. You also have students who study empirical industrial organization, bringing those techniques to bear in environmental economics. In terms of the percentage of work that is done today that is more theoretically based, my impression is that theoretical research really has declined, in terms of the number of purely theoretical papers written or even papers that are using theoretical approaches.\

The emphasis on theory has also changed during the time I have been teaching. When I was teaching a graduate class a few years ago, we were talking about discounting issues and, of course, the Ramsey formula. Students had heard of the Ramsey formula, but when I asked students if they knew who Frank Ramsey was, I was surprised to find that they didn't know. The fact is, I think there has been this shift. When I teach environmental economics, the preparation of students in terms of econometric techniques is really quite impressive. I've got to say that has really been ramped up. That represents an important change in the profession ... 

A version of this article first appeared on Conversable Economist.