Oral-History:C.R. Rao

About C.R. Rao

Dr. Calyampudi Radhakrishna Rao is a mathematician and statistician who is professor emeritus at Pennsylvania State University and Research Professor at the University at Buffalo. Rao was born in Hadagali, Bellary, Madras Presidency, India and earned a PhD degree from King's College in Cambridge University under R. A. Fisher in 1948, and a Sc.D. degree, from Cambridge, in 1965. Rao spent over 40 years at the Research and Training School at the Indian Statistical Institute, and discovered the Cramér–Rao bound and the Rao–Blackwell theorem. He is the author of 14 books and has published over 400 journal publications.

About the Interview

C.R. RAO: An Interview Conducted by Michael Geselowitz, IEEE History Center, 5 May 2021

Interview #854 for the IEEE History Center, The Institute of Electrical and Electronics Engineers, Inc.

Copyright Statement

This manuscript is being made available for research purposes only. All literary rights in the manuscript, including the right to publish, are reserved to the IEEE History Center. No part of the manuscript may be quoted for publication without the written permission of the Director of IEEE History Center.

Request for permission to quote for publication should be addressed to the IEEE History Center Oral History Program, IEEE History Center, 445 Hoes Lane, Piscataway, NJ 08854 USA or ieee-history@ieee.org. It should include identification of the specific passages to be quoted, anticipated use of the passages, and identification of the user.

It is recommended that this oral history be cited as follows:

C.R. Rao, an oral history conducted in 2021 by Michael Geselowitz, IEEE History Center, Piscataway, NJ USA.

Interview

Interviewer: Michael Geselowitz

Interviewee: C.R. Rao

Location: Virtual

Date: 5 May 2021

Geselowitz:

Good afternoon everybody. I’m Dr. Michael Geselowitz, the executive director of the IEEE History Center, and I’m here on Zoom conducting an interview with Professor Dr. C.R. Rao. Also participating are his daughter, Teja Rao, a former student, Dr. T. Krishna Kumar, and also Dr. Raghuveer Rao.

Professor Rao, we actually are indeed excited and privileged to have you with us today.

Rao:

Okay.

Geselowitz:

This is part of an oral history project, which is being conducted under the auspices of the IEEE Signal Processing Society. This is on the occasion of their upcoming platinum jubilee in 2023. So, thank you very much for giving us some of your valuable time. I’ll start with the first question, which is an unusual question, but it was proposed by the Signal Processing Society. They say that behind every successful man, there is a woman. In your case, Professor Rao, who is that woman?

Rao:

Thank you for picking me for this project, on this Platinum Jubilee celebration for the Signal Processing. I had my mother who instilled in me discipline. Then my wife, Bhargavi, who gave me all the support that I needed. And after my wife passed away, I have my daughter, Teja.

Geselowitz:

So, my next question, Professor Rao, IEEE is an engineering association, and I’ve interviewed many engineers, but you are considered a mathematician. So, we were wondering, who influenced you to choose mathematics as a career?

Rao:

Oh in my earlier career, it was my father, then Dr. Vommi Ramaswamy of Andhra University and Prof. Mahalanobis. Later it was Professor R.A. Fisher.

Geselowitz:

I see, so I’m very excited to hear you mention the name of R.A. Fisher, who’s considered by many to be the father of modern statistical science, and yet, one seldom hears of his graduate students; you seem to be one of the, one of his few direct students. Could you please tell us a little bit about your experience of being a student of R.A. Fisher?

Rao:

My interaction with R.A. Fisher was really rewarding. He would ask a problem, searching for the development of a solution method.

Geselowitz:

So, that’s fascinating, Professor Rao. Thank you. I’ll also note, I actually saw the family documentary. Mague(?) [phonetic] was kind enough to send me a link, so Teja, I know you have a lot of images, presumably, that you used in that, and so some of those would be useful for us, as well, if you could share them later, after the interview.

T. Rao:

And I can send you the photographs if you want.

Geselowitz:

Yes, that would be very helpful.

T. Rao:

Yes, I could send you the photographs.

Geselowitz:

We can splice those into Professor Rao’s web page. So, Professor Rao, everybody who knows you and your work knows you as C.R. Rao. Is that actually your name? Is that a nickname?

Rao:

Most call me C.R. Rao. There is an anecdote regarding my name. I was on a trip and my luggage was lost and they were to deliver it to my room later that morning. I got a call from a student who was looking after me saying, “Professor Cramer Rao. They’ve found your bag”. I tried to explain that the name was C.R. Rao, not Cramer Rao. He was confused because he had studied the Cramer-Rao Bound.

Geselowitz:

That is an, an excellent, an excellent anecdote. I guess in some countries, they’re used to using initials and others they’re not. So, obviously you’ve had an exemplary career. You’re considered a living legend in statistics, but actually, your contributions to statistics impacted so many other fields, social, physical, biological sciences, engineering, even linguistics, and of course signal processing, which is, which is why the Signal Processing Society considers you one of their pioneers that they want to have interviewed for their jubilee. You’ve been honored more times than I can count. I guess what most impressed me in the documentary was that you received the Presidential Medal of Honor from President Bush. And I fairly feel that your life story is an inspiration to the entire mathematical community of the world, but particularly to the IEEE Signal Processing Society community. I know you had very limited time. The Society has sent you additional questions that you can answer at your leisure and we’ll have those as a written record. With Teja’s help you can send those to us at your convenience. But I was wondering while we have you on video, if there’s anything else that either you or your daughter or your students Raghuveer or Krishna would like to add on tape at this time? Is anyone interested in speaking?

T. Rao:

I have some beautiful photographs of my father right from the time he was a student, and here is one, I don’t know if you can see it.

Geselowitz:

Yes, yes, we can see it.

T. Rao:

Yeah, it’s my father with Fisher going through a paper, just before the presentation at a conference and for me it’s been very moving showing this photograph, because it hung in our living room for years and years and years, and someone caught it at the right moment.

Geselowitz:

Wow, that’s beautiful. Yeah, it’s very interesting, and I look forward to getting the actual copies of those so we can use. It’s nice on the video, but it won’t show up well on the website unless we have a scan.

T. Rao:

Yes.

Geselowitz:

By the way, my son-in-law’s a pre-university mathematics teacher, and I told him that I would be interviewing this well-known statistician, and he asked “what is his name?”, and I told him, C. R. Rao. Statistics isn’t really his field, so he asked what are his theorems? And I said, well, I’m not a mathematician. you have to look on Wikipedia. I can’t really help you. I said, but I do know that he was a student of Fisher at Cambridge… and he was floored.

T. Rao:

Yes.

Geselowitz:,

You know, and no other of Fisher’s students are still with us and still contributing, so it’s amazing. Before I close, I’d like to give Professor Rao the last word at the end but I just want to thank Professor Rao for his time--

Raghuveer Rao:

I also had just a sentence or two to say.

Geselowitz:

Okay.

Raghuveer Rao:

A simple search of the Signal Processing Society literature, for example, if you took the IEEE Transactions on Signal Processing and looked for the Cramer Rao Bound or the Cramer Rao Inequality, this search turns up several thousands. If you were to focus from the beginning of the year, with that particular key word, you’re going to see several hundreds already, and that tells you something about the staying power of, the longevity and the continual influence of that one great results that Professor Rao was obviously a key part of. That’s about what I wanted to say.

Geselowitz:

Thank you. That’s a great, a really great point. There’s so many things that seem hot theories at the time, but then 10, 20 years, no one’s citing them anymore, and that’s really something that after all these years, it’s one of the most cited papers. It’s incredible.

T. Rao:

I think the video, the documentary that we sent you has been removed. I send you a new one because I had to edit something in it.

Geselowitz:

Okay, thank you, Teja. And Professor Rao, obviously thank you so much. You’ve made, had such an impact on society, but I’d also like to thank the IEEE Signal Processing Society. They made it possible for us to talk to you today, and particularly Dr. Raghuveer Rao and Dr. Krishna Kumar, but also, who are with us, but also Dr. K.V.S. Hari. Dr. Mos Kaveh, and of course, mostly I want to thank your daughter, Teja, for sharing you with us. We really appreciate it. So, would you like to say any final words?

Rao:

It’s my pleasure. Thank you for doing this.

Geselowitz:

You, you’re very welcome. Thank you again.

T. Rao:

And thank you very much for taking the time to do the interview with my father.

Geselowitz:

It was my pleasure. It’s a great honor. We do a lot of these interviews, and all of them are an honor, but this is a particular great honor for me, so it’s much appreciated.

T. Rao:

Thank you. Thank you.

Rao:

Thank you.