Johannes Ledolter

Johannes Ledolter (August 26, 1950 – Nov 5, 2023) was an applied statistician. He was a chaired Professor of Business Analytics and of Statistics/Actuarial Science at the University of Iowa as well as Emeritus Professor at the Wirtschafts Universitat in Vienna, Austria. He also served as Associate Investigator, Center for Prevention and Treatment of Visual Loss for the Iowa City VA Health Care System.

Ledolter authored 10 books and more than 150 journal articles and chapters. He was a Fellow of the American Society for Quality and the American Statistical Association. He is also an Elected Member of the International Statistics Institute. He served as Associate Editor of the Journal of Business and Economic Statistics, the Journal of the American Statistical Association, Quality Engineering, and the Journal of Forecasting. A Fulbright Scholarship brought him to America initially. He served as the Program Chair and local organizer of the NBER-NSF seminar on time series in both Iowa City and Vienna. He was the Program Chair of the 1992 Joint Statistical Meetings.

Education and Early Life
Johannes Ledolter was born 1950 in Murzzuschlag Austria, a tiny town in the Alps, as the only child of a schoolteacher and part-time bookkeeper. The valley was emerging from World War II, and though the family struggled to survive on food stamps and ration tickets, Johannes enjoyed his childhood, in a place where school ran only half a day leaving the afternoons for hiking in the mountains and skiing. His mathematical training was in the classical and formal tradition, which favored memorization and practice calculating without pen and paper. Johannes Ledolter was part of the first cohort of students to graduate from a newly established gymnasium in his valley in the Austrian Alps. From Gymnasium, he went to the University of Vienna. He never finished his undergraduate studies because he was selected as a Fulbright scholar to study in the United States, where as luck would have it, he went directly into a master's program.

At the time modern statistics was in its infancy, and Ledolter was convinced that the most advanced work was happening in the United States, and particularly at the University of Wisconsin-Madison. At Madison, Ledolter studied under and worked closely with two of the late 20th century giants in the field: the British statistican, George E.P. Box and the British-Taiwanese statistician, George Tiao.

Box sparked Ledolter’s excitement in statistics, by introducing him to time series analysis, Bayesian statistics, and statistical design of experiments. Ledolter was Box's teaching assistant for several years and Box later became Ledolter's thesis advisor, mentor, and good friend. Ledolter earned a M.S., Statistics, University of Wisconsin-Madison, 1972 He also earned a M.S., Social and Economic Statistics, University of Vienna, 1974 and his Ph.D., Statistics, University of Wisconsin-Madison, 1975.

Philosophy of Statistics
Professor Ledolter's approach to statistics was that of a statistical sleuth. "Statistical sleuthing is the process of using statistical tools to answer questions of interest. It includes devising experiments to unearth hidden truths, describing real data using tools based on ideal mathematical models, answering the questions of interest efficiently, verifying that the tools are appropriate, and snooping around to see if there is anything more to be learned." When he was a grad student at the University of Wisconsin, George Box ran a weekly Monday night seminar in his basement where, over beer and chips, any scientist with an interesting research project could present his work and get feedback from the group of enthusiastic statisticians gathered there. This was heady stuff for Ledolter the young graduate student. Each week, he would foray into presentations of some of the latest data being collected at the large research university and participate along with the University's greatest statistical minds in parsing it for what new statistical insight would best serve the analysis. From Box's regular Monday night seminars, Ledolter adopted a philosophy that would serve him throughout his career: focus on statistics as a tool to apply to the real world. Let the real world problems dictate the appropriate statistical method needed. And if no appropriate method existed, work to invent one for the task. For Ledolter, it was not enough be a Bayesian, or Stochasticist, or any particular school of statistics. As an applied statistician, Ledolter mastered all available methods, but it was the real world problem that called forth which statistical method was necessary and suitable to the task. As an applied statistician, Ledolter's unique contributions to statistics was his ability to accumulate an enormously broad portfolio by following this approach for more than 50 years. Over the course of five decades he brought this extraordinary broad portfolio of solutions, to assist anyone who brought him a problem to solve. Ledolter's method was collaborative. He was curious and would listen to any idea he thought was interesting. He explored the world by looking through the many faceted lens of statistics. His portfolio of work was so diverse as to include problems to air pollution for the E.P.A., speed limits effect on traffic deaths, risk assessment in accounting, design of experiments, optical nerve trauma, surgical suite optimization, quality improvement, hydrology, data-mining and text-mining, econometric forecasting and management techniques. By seeking the appropriate statistical method for the researcher's question, he learned about the world.

Teaching Experience and Honors
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Ledolter taught beginning and advanced courses on statistical methods at the University of Iowa (Tippie College of Business and Department of Statistics/Actuarial Science), Vienna University of Economics and Business, Institute for Advanced Studies (Vienna), Stanford University, University of Chicago Booth School of Business, Yale University, and Princeton University. He received a call to return to Austria twice, first from the Technical University of Vienna, and later from the WU. He finally accepted the call to join the Vienna University of Economics and Business (Wirtschaftsuniversität). There, Hannes served as a faculty member and professor at the Institute for Statistics and Mathematics from 1997 to 2002. Maintaining life on two continents, however, was hard on the family, so subsequently, Ledolter held a 25% position at the Wirtschaftsuniversität and a 75% appointment as the Robert Thomas Holmes Professor of Business at the Henry B. Tippie College of Business, as well as Professor of Statistics and Actuarial Science at the University of Iowa from 2002 to 2015. Since 2015, Hannes has held the title of Emeritus Professor at the Wirtschaftsuniversität.

Ledolter taught courses on Mathematical Statistics, Linear Models, Regression Analysis, Analysis and Design of Experiments I and II, Multivariate Statistical Techniques, Time Series Analysis I and II, Recent Topics in Time Series Analysis, Forecasting, Probability and Statistics for the Engineering and Physical Sciences, Biostatistics, Business Analytics for MBA, Advanced Business Analytics for MBA, Business Analytics for Executive MBA, Statistical Methods for Quality and Productivity Improvement, Statistical Methods (undergraduate) I and II, Applied Statistical Methods in Forestry and Environmental Studies, introductory and advanced courses on Statistical Methods (in German).

Consulting
Ledolter presented short courses for business and industry on Statistical Modeling, Time Series Analysis and Forecasting, Statistical Methods for Quality and Productivity Improvement, and Business Analytics and Data Mining.

Ledolter has consulted with US and European companies including Ford Motor Company, Procter and Gamble, Northstar Steel, HON IndustriesMeredith Publishing, Iowa Pork Producers, State of California, Ticona/Celanese, American Express, Bemis Corporation, Lenzing Fiber (Austria), Telekom Austria.,

Personal life
While at the University of Wisconsin, Ledolter met Lea VanderVelde, then a law student. The two of them built their lives in academic research. They continued as life partners for 50 years, each pursuing their intellectual curiosity. They married in 1977 and had three children.

Publications
Ledolter, J., Schebeck, F. and Thury, G.: Forecasting Using Leading Indicators: Some Empirical Evidence for Austria, Vandenhoeck and Ruprecht, Göttingen, 1981

Abraham, B. and Ledolter, J.: Statistical Methods for Forecasting, Wiley & Sons, 1983 (Second edition, 2005)

Hogg, R. V. and Ledolter, J.: Engineering Statistics, Macmillan, 1987

Hogg, R. V. and Ledolter, J.: Applied Statistics for Engineers and Physical Scientists, Macmillan, 1992

Ledolter, J. and Burrill, C. W.: Statistical Quality Control: Strategies and Tools for Continual Improvement, Wiley & Sons, 1999

Burrill, C. W. and Ledolter, J.: Achieving Quality Through Continual Improvement, Wiley & Sons, 1999

Abraham, B. and Ledolter, J.: Introduction to Regression Modeling, Duxbury Press, 2006

Ledolter, J. and Swersey, A.J.: Testing 1 – 2 – 3: Experimental Design with Applications in Marketing and Service Operations, Stanford University Press, 2007

Ledolter, J. and Hogg, R. V.: Applied Statistics for Engineers and Physical Scientists, Prentice Hall, 2009

Ledolter, J., Book Review, The Statistical Sleuth (2nd ed.) by Fred L. Ramsey and Daniel W., 57 The American Statistician 145, May, 2003.

Ledolter, J.: Data Mining and Business Analytics, Wiley & Sons, 2013

Ledolter, J. and VanderVelde, L.S.: Analyzing Textual Information: From Words to Meanings through Numbers, SAGE Publishing (Quantitative Applications in the Social Sciences), 2021.