SJS Publishes Special Section in Honour of Elja Arjas

Scandinavian Journal of Statistics has just published a special section in honour of Elja Arjas, Professor Emeritus, University of Helsinki, Finland. We congratulate Elja on his 80th birthday (February 2023) and acknowledge his contribution to the field of statistics and to SJS.

Elja has made an influential and unforgettable contribution to the training of a whole generation of statisticians and statistics professors in Finland. Many current statistics professors and university lecturers in universities, and research professors and senior researchers in research centers in Finland have some close connection to Elja: many are Elja’s former PhD students (like Mikko J. Sillanpää, SJS Editor-in-Chief), former postdoctoral researchers (like Sangita Kulathinal, SJS Editor-in-Chief), or Elja has been at least PhD opponent/pre-examiner or docentship evaluator for them. One may introduce an “Arjas’ number” similar to the Erdös number in mathematics. This is simply because the number of Elja’s academic descendants in Finland is huge.

Elja’s role in raising the quality of SJS has also been invaluable. Elja served as SJS Editor for the years 1991–1994 and he has thought of SJS as “our [Nordic] statistics journal” as detailed in the article “Conversation with Elja Arjas” in this issue. While Elja was Editor, he made a facelift and profiled SJS to a broader audience and made it an international statistics journal in a true sense. Thirty years on, we have seen SJS rising to the international level and publishing articles of high quality.

Five distinguished scientists were invited to write about topics related to Elja’s research interests. The resulting five articles published in the special section of this issue are:

1. The first article is a summary of Jukka Corander’s (a former postdoctoral researcher of Elja) conversation with Elja about his career. (Open Access)

2. Sander Greenland, a well-respected (quite gentle) critic of p-values, has written about “Divergence vs. Decision P-values: A Distinction Worth Making in Theory and Keeping in Practice”. A further discussion of the article will be published in a subsequent issue of SJS.

3. Respecting Elja’s thinking in Bayesian terms, we invited Persi Diaconis, the world renowned mathematician/statistician, to write about Bayesian statistics. Persi’s contribution is in “Approximate exchangeability and de Finetti priors in 2022”.

4. Ørnulf Borgan, with whom Elja communicated frequently, provided an article, written jointly with his collaborators. The title of the article is “Use of multiple imputation in supersampled nested case-control and case-cohort studies”. (Open Access)

5. Terry Speed and Elja Arjas were both doing research at the same time at the University of Sheffield, United Kingdom. They also had some joint papers together. Here Terry and his co-author, Ingrid M. Lönnstedt, contributed an article “RUV retrieves unknown experimental designs”.