“It’s fair to say that a person can only celebrate a 100th birthday once in a century,” pronounced Joe Blitzstein, Professor of the Practice, in the Harvard Department of Statistics. Leaning towards an audience of 100 gathered at the Harvard SOCH Hilles building, he added, “Today, we celebrate with our beloved colleague Herman Chernoff his birthday and 70 plus years of contributions to the field of statistics.” With these words, Prof. Blitzstein launched the May 5th Centennial Celebration of Emeritus Faculty Herman Chernoff and his research and teaching legacy. The day featured a full program, including a virtual tribute video from former colleagues and students, a Q&A session with Professor Xiao-Li Meng, and research presentations from former colleagues Professors Joseph (Jay) Kadane, Tian Zheng, and Joseph Gastwirth. For making this day happen, we would like to thank the Chernoff family, including his daughters, Miriam and Ellen Chernoff, and Miriam’s husband, Stan Morse. We would also like to express our deepest condolences to Professor Chernoff and his family for the recent loss of Judith Chernoff, his wife of over 75 years.
In acknowledgement of Prof. Chernoff’s birthday, we would like to provide an overview of Chernoff’s career highlights as well as the emerging themes from the symposium. The event celebrated Chernoff as a statistician, educator, and mentor, who has cultivated lasting relationships and possesses a great sense of humor.
Career Highlights
Chernoff started his career when he completed a B.S. in mathematics and a minor in physics in 1943 from City College in New York. For a year and a half, he worked as a physicist with the US Navy by building and fixing electronics. His use of statistical ideas in the Navy convinced him to return to school to first pursue a master’s and then a PhD in applied math at Brown University, where he was supervised by his dissertation advisor Professor Abraham Wald (Bather, 1996, p.336). Subsequently, Chernoff held faculty positions at the University of Illinois (1949-1952), Stanford University (1952-1974), MIT (1974-1985), and Harvard University (1985-1997); he continues to be Professor Emeritus at Harvard and MIT.
Chernoff’s contributions to the field include work on large sample theory, experimental design, sequential analysis, methods of presenting statistical data in visual form, and statistical decision making. In addition to his research, Professor Chernoff is known for his enthusiasm for mentoring a generation of outstanding statisticians. His interest in providing professional opportunities for young researchers led him to suggest the annual New England Statistics Symposium (NESS), established in 1987, for example. In honor of Chernoff’s contribution to NESS and to the profession in general, the New England Statistical Society established the Chernoff Excellence in Statistics Award in 2019 (the most recent awardee was Harvard Statistics PhD alumna Professor Nan Laird). In recognition of his work, Chernoff has received honors from the National Academy of Sciences and the American Academy of Arts and Sciences, to name a few, and has been selected as a Fellow of the American Statistical Association and the Institute of Mathematical Statistics.
An Expansive, Curious Mind
In an intimate Q&A conversation with Prof. Xiao-Li Meng, Chernoff revealed to the audience his reasons for switching from mathematics and physics to statistics. Chernoff described a pivotal moment in his grad student career when he read a paper on generalizing the testing of hypotheses and estimation by the scholar Abraham Wald in a reading course: “Wald’s paper struck me because, while it didn’t involve intensive mathematics, it confronted the fundamental idea that the test of a hypothesis or an estimation of a parameter leads to a conclusion and that conclusion should have an economic, real-world consequence.” Turning from Meng to the audience, Chernoff concluded, “and that’s what converted me to being a statistician!” Chernoff added that he remembered also reading papers by the statisticians Neyman and Pearson that exposed him to the idea that when evaluating a hypothesis, it was important to consider alternatives to that hypothesis. These experiences highlighted what drew Chernoff to statistical thinking: his interest in connecting theory to applications and solving and quantifying problems of uncertainty. Although he was trained as a mathematician and physicist, Chernoff relished the opportunity to tackle a new field, statistics.
In his career as a statistician, Chernoff embraced working in both applied and theoretical areas, a rare feat today because of how specialized statistics has become. From the start of the Centennial Celebration, Blitzstein emphasized Chernoff’s multi-faceted work in statistics, pointing out his applied and theoretical, Bayesian and frequentist, and parametric and nonparametric approaches. The three research talks given by Chernoff’s colleagues also showcased the span of his research interests and influence. While the first talk by Professor Emeritus Jay Kadane of Carnegie Mellon University focused on the use probability theory to analyze handwriting in a court case, the second talk by Professor Tian Zheng of Columbia University discussed methods for detecting influential variables in high dimensional data, specifically genetic data. Additionally, Professor Joseph Gastwirth of George Washington University spoke about his collaboration with Chernoff on the use of L-statistics in measuring economic inequality. Representing such a wide range of interest and expertise, these talks were a reminder of Chernoff’s curiosity and expansive thinking.
In his interview with Prof. Meng, Chernoff further explained why the manifold applications of statistics, such as in genetics, clinical trials, or economics, have motivated his career. Chernoff reflected on his research legacy, “People regard me as a theoretical statistician, but I’ve decided in recent years that I’m really an applied statistician. My theoretical insights have relied upon my work in thinking about applied problems.” A salient example of Chernoff taking inspiration from applied problems was when he created Faces. Designed by Chernoff while he was working at Stanford, Faces was a data visualization tool that he developed to help researchers analyze multivariate data (by presenting data as faces). While Chernoff was still interested in developing statistical theory, he was also invested in working on more applied problems like how to effectively display multidimensional data.
The Centennial Celebration, from the Q&A with Prof. Meng to the research talks to Prof. Blitzstein’s anecdotes, illustrated Prof. Chernoff’s life-long love of learning in statistics and other fields. While his curiosity drove him to study statistics for the first time as a graduate student, it also motivated him to seek tips on the programming language R. Describing Chernoff’s budding interest in R, Blitzstein said, “I was pretty impressed that he was still coding; usually brilliant mathematicians get their PhD students to do all the coding, but Herman wanted to test out his methods by carrying out the simulations himself.” Blitzstein added, “One day, Herman came into my office and asked for a book on C because ‘R was too slow for him,’ and I was even more impressed with that!” It’s clear that Chernoff has maintained a zest for learning new things and taking on new challenges.
A Generous Educator and Mentor
Having taught statistics in the department for many years, Chernoff still encouraged and mentored undergraduates once he became an emeritus faculty. Blitzstein reminisced about when their offices faced each other, and he would routinely return to his office and find Chernoff ensconced in a conversation with a student. “My students from Stat 110 would receive homework help from this friendly man in his 80s without even realizing that he had pioneered some of the methods they were using 60 years before,” marveled Blitzstein. This story reveals how Chernoff maintained a life-long interest in nurturing students’ enthusiasm for and competence in statistics. In addition, Chernoff demonstrated his interest in supporting the intellectual growth of younger students by publishing books such as “Elementary Decision Theory” in 1959 and “Algebra I for Students Comfortable with Arithmetic” in 2001. Holding his own autographed version of “Elementary Decision Theory,” Blitzstein commended the book for being straightforward and accessible to high school students but also for addressing some of the most pressing questions in statistics.
While the Centennial Celebration highlighted the impact of Prof. Chernoff’s work, some of the most memorable moments during the conference were when colleagues and former students shared their stories about his tips and coaching on their research and careers. For example, when Prof. Gastwirth was a junior colleague at Stanford, he was thrilled to be asked for the first time to be a reviewer of an article and was willing to offer a tight turnaround with his comments. Sharing the following advice from Chernoff that he’s adhered to ever since, Gastwirth said, “When I told Herman about finishing the review within a week, he said, ‘No, no – you have to think about the worst possible thing that can happen to delay you (e.g. you get sick) and then you double that amount of time!’”
Harvard Statistics Professors Jun Liu and Xiao-Li Meng both shared anecdotes about Chernoff’s mentorship. Shortly after Liu arrived as a junior faculty at Harvard, he was drafting his first paper in which he was a first author and Chernoff offered to read his paper. Liu recalled, “I felt a little intimidated by such a renowned statistician offering to read my paper, but Herman read it and provided such useful, line by line comments that it was ultimately accepted into the Annals of Statistics.” During his Q&A with Chernoff, Meng highlighted an episode that occurred earlier in his career as a PhD student in the department. In preparation for his qualifying exam, Meng had printed a copy of his paper and commenced to read every page to his committee. Chernoff paused the perusal with a question that Meng promptly glossed over. Chernoff interjected, “Xiao-Li, you are not answering my question.” From this moment, Meng learned that it was not sufficient to pursue important research questions; he must also learn how to communicate effectively to succeed as a researcher.
Lasting Relationships with Colleagues, Family, and Friends
The warm outpouring of thanks and congratulations to Prof. Chernoff is a testament to the close-knit relationships that he has maintained. During a tribute video and in person toasts, friends and family, as well as former colleagues, students, and postdocs from all over the country, acknowledged Chernoff’s impact on them. Attendees reminisced about grad student lunches at a pizza parlor and cozy gatherings at the Chernoff home, and they shared some of Chernoff’s favorite interests and things: politics and travel, dogs and Swiss orange chip ice-cream. One attendee, the son of a former high school classmate, marveled at the journey that Chernoff had taken as a child during the Great Depression from a family of modest means to becoming an influential statistician. Sharing their regret that she could not participate in the symposium, many attendees paid tribute to Judith Chernoff by reflecting on her warmth and humor and lauding the couple’s marriage of over 75 years.
A Sense of Humor
Throughout the Centennial Celebration, there were also many moments that brought Prof. Chernoff’s sense of humor into the foreground. A primary example was when he narrated a story about his analysis of the Massachusetts lottery. When Chernoff arrived in Boston to work at MIT, the lottery had only been in place for about 500 days. After a statistician had shown that the lottery was likely to have had some repetitions but didn’t, it dawned on Chernoff that the lottery was probably fixed. Chernoff elaborated, “When I realized that the lottery was fixed, I thought that I should announce it, but then maybe the gangsters would not like that and would assassinate me. On the other hand, when I told the Area Chair at MIT, Harvey Greenspan, he suggested that if it was fixed, I should take advantage of it!” In the end, instead of “taking advantage of it,” Chernoff started to analyze the lottery and generated a paper that provided advice to people on how to select winning combinations.
Chernoff’s words are emblematic of his approach to life and his relationships with others. While he cares deeply about the theory and applications of statistics and has committed his career to pursuing meaningful questions, Chernoff also appreciates doses of levity and humor and relished engaging with Meng and other former colleagues and students at the symposium. The celebration was truly a once in a century opportunity to recognize Chernoff’s contributions as a researcher, educator, and mentor. We look forward to celebrating with Prof. Chernoff again at his 105th birthday!
The following photos were provided by Matthew Esmaili Mallory:
The following photos were provided by Sally Thurston:
References:
John Bather. "A conversation with Herman Chernoff." Statist. Sci. 11 (4) 335 - 350, November 1996. https://doi.org/10.1214/ss/1032280306