EVENT REPORT

Report on the 43rd
European Conference on Information Retrieval(ECIR 2021)
Raffaele Perego and Fabrizio Sebastiani
Istituto di Scienza e Tecnologie dell’Informazione
Consiglio Nazionale delle Ricerche
56124 Pisa, Italy
firstname.lastname@isti.cnr.it
Abstract
The 43rd European Conference on Information Retrieval (ECIR 2021), organized under theauspices of the Information Retrieval Specialist Group of the British Computer Society (BCSIRSG), took place between March 28 and April 1, 2021. As sadly customary in these darktimes, the conference was held entirely online, due to the COVID-19 pandemic. According
to the original plans, it should have instead taken place in Lucca, a small Italian town in
Tuscany, Italy, which enjoys a beautiful, extremely well-preserved historic centre.

1Structure of the Conference

ECIR 20211 had the traditional structure of previous ECIR conferences, i.e., its program consistedof five days, with the first day (March 28) devoted to tutorials and the Doctoral Consortium, thethree days that followed (March 29 to 31) occupied by the main conference, and the last day(April 1) devoted to satellite workshops and the industry day.
On the first day, two full-day (FD) tutorials and six half-day (HD) tutorials were offered, onthemes ranging from “Reinforcement Learning for Information Retrieval” (FD – by Alexander
Kuhnle, Miguel Aroca-Ouellette, Murat Sensoy, John Reid, and Dell Zhang), “IR From Bag-ofwords to BERT and Beyond through Practical Experiments” (FD – by Sean MacAvaney, Craig
Macdonald, and Nicola Tonellotto), “Fake News, Disinformation, Propaganda, Media Bias, andFlattening the Curve of the COVID-19 Infodemic” (HD – by Preslav Nakov and Giovanni DaSan Martino), “Operationalizing Treatments against Bias” (HD – by Ludovico Boratto and MirkoMarras), “Large-Scale Information Extraction under Privacy-Aware Constraints” (HD – by Rajeev Gupta and Ranganath Kondapally), “Search Among Sensitive Content” (HD – by Graham
Mcdonald and Douglas Oard), “Adversarial Learning for Recommendation” (HD – by Vito Walter
Anelli, Yashar Deldjoo, Tommaso Di Noia, and Felice Antonio Merra), to “Biomedical Data, Text1

https://www.ecir2021.eu/

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Retrieval and Semantic Processing” (HD – by Francisco Couto). The 2nd tutorial in this list was
the best-attended, with 149 attendees.
In parallel to the tutorials, the Doctoral Consortium was held, which offered five PhD students
from around the world the opportunity to discuss their research plan with individually chosen
mentors.
The three days of the main conference featured 3 keynote talks, 50 full paper presentations (outof 211 submissions, for a 23.7% Acceptance Rate), 11 presentations from the Reproducibility Track(47.8% AR), 7 presentations of papers recently published on the Information Retrieval Journal, 12
short-paper presentations of the CLEF 2021 Labs, 39 poster presentations of short papers (28.5%AR), 15 demos (48.4% AR), and a panel. Submissions were received from 40 different countries,with China, India, Germany, the US, and the UK, ranking (in this order) as the top 5 countries interms of number of submissions. The 3 keynotes were by Ricardo Baeza-Yates (on “Ethics in AI”– the best-attended session in the entire conference, with 214 attendees), Ahmed H. Awadallah(winner of the Karen Sparck Jones Award – on “Learning with Limited Labeled Data: The Roleof User Interactions”), and Ophir Frieder (on “Untraditional (Computer) Medicine”). We areparticularly grateful to Ricardo Baeza-Yates for accepting to give his keynote with a one-dayadvance notice, as a replacement of the originally planned keynote by Francesca Rossi, who hada last-minute impediment.
The panel, held in a plenary session on the 3rd day of the conference, was on the theme of “OpenAccess and IR Literature”. It was coordinated by Djoerd Hiemstra, with invited panelists Hassina
Aliane (CERIST, Algeria), Ralf Gerstner (Springer – the publisher of the ECIR proceedingsfor the last 20 years), Min-Yen Kan (National University of Singapore – former director of theACL Anthology), Haiming Liu (University of Bedfordshire – representative of BCS IRSG), JoãoMagalhães (Universidade Nova de Lisboa – General co-Chair of ECIR 2020), Hussein Suleman(University of Cape Town), and Min Zhang (Tsinghua University – ACM TOIS Editor-in-Chief).
The discussion dwelled on the growing request from the scientific community to publish scientific
literature (and, specifically of relevance to the present context, the ECIR proceedings) in an open
access way (see also [Hiemstra et al., 2020]), and touched upon several sensitive issues, such as
the fact that many research institutions simply cannot afford subscribing to the digital libraries
that host IR-related publications, that this prevents young researchers in those institutions (andin entire countries) to take up IR as a subject (instead of, say, NLP, whose literature is almost
100% free – with no cost for authors and readers alike – thanks to the ACL Anthology), and thatexperiences indicating that this state can be changed abound (e.g., the proceedings of top NLP
conferences such as ACL, NAACL, EACL, EMNLP, and journals such as JAIR and JMLR). A
straw poll conducted among the attendees at the end of the panel indicated that these attendees
believe that the ECIR proceedings should go open access (97% of respondents voted in this way),that the model to imitate should be that of the ACL Anthology, i.e., zero cost for authors, zero
cost for readers (59% of respondents), and that the costs of running such an endeavour should
be covered via a combination of volunteer work, sponsor money, and conference registration fees
(65% of respondents); concerning the last question, only 24% of respondents believe that article
processing charges should be the solution.
Finally, the last day of the conference hosted the Industry Day (organized by Roi Blancoand Fabrizio Silvestri) and five satellite workshops, on themes ranging from “Algorithmic Bias in
Search and Recommendation” (organized by Ludovico Boratto, Stefano Faralli, Mirko Marras, andACM SIGIR Forum

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Giovanni Stilo), “Bibliometric-Enhanced Information Retrieval” (organized by Ingo Frommholz,
Philipp Mayr, Guillaume Cabanac, and Suzan Verberne), “Mixed-Initiative Conversational Systems” (organized by Ida Mele, Cristina Muntean, Mohammad Aliannejadi, and Nikos Voskarides),“Reducing Online Misinformation through Credible Information Retrieval” (organized by Fabio
Saracco and Marco Viviani), to “Narrative Extraction from Texts” (organized by Ricardo Campos,Alı́pio Jorge, Adam Jatowt, Sumit Bhatia, and Mark Finlayson).
The Industry Day presented interesting success stories by IR researchers working in prominentcompanies, and featured two keynote speeches. The first keynote was on “Search and Discovery forFinance, in Practice” by Edgar Meij (Bloomberg), while the second, “Geometric Deep Learning:
From Euclid to Drug Design”, was given by Michael Bronstein (Twitter and Imperial College).
The proceedings of ECIR 2021 are published by Springer Nature in its Lecture Notes in Computer Science series [Hiemstra et al., 2021].

2The Online Experience

Organizing ECIR 2021 was challenging, since, like for many other online conferences, it required
making preparations and bookings for a regular, in-presence conference (which we believed, orwanted to believe, would be the case until 6 months before the event), and eventually setting up
things for the conference to be run completely online. Concerning the latter, the bar had been setvery high by the organizers of ECIR 2020, who had managed to set up an online-only conferenceof astounding quality with very little advance notice, given that Europe had started to realize theimpact that pandemic would have, barely weeks before ECIR 2020 took place.
Three online platforms, i.e., Whova, Zoom Webinars, and Gather Town, were used for theconference. As for many other conferences, Whova was used to generate an online, mobile-friendly
conference schedule to be used by all attendees as the only entry point to the conference. The
Whova schedule pointed to Zoom webinars, that were used as the platform for running all ECIR
2021 events other than the short paper presentations and the demos, and to Gather Town, which
was used for the short paper presentations and the demos. Gather Town provides a simulated
environment where attendees can meet and interact, and was thus also used during coffee breaks
and lunch breaks for attendees to meet spontaneously, discuss, and network.
Going entirely online also means entirely reconsidering the registration fee structure. We optedfor asking a flat, nominal registration fee (150 EUR) to authors only, in a one-author-per-paper
fashion. Given that the about 125 paying authors, together with the contributions from thesponsors (Bloomberg Engineering, SIGIR, Amazon Science, eBay, Google, Signal, TextKernel,
Springer), allowed us to cover our costs, we decided to grant a free registration to all otherattendees, with the goal of maximizing participation, especially from developing countries. This
generated a high number of registrants (more than 1,100) from no less than 63 countries, withGermany, the US, the UK, the Netherlands, and Italy, ranking (in this order) as the top 5 countries
in terms of registrants. Of the more than 1,100 registrants, 1,028 logged into the conference atleast once; 40% of them used the mobile app at least once while 85% of them used the web app
at least once.
We all wish that future ECIRs will be back to the in-presence format, where speakers, attendees, and sponsor representatives will be able to meet face-to-face and network without thesomehow clumsy barriers generated by the online platforms.
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The online-only format does not have negative aspects only, though; it’s just a different experience from in-presence conferences. While many “regular” attendees of ECIRs obviously complained that interaction and the experience is not the same as when we meet in presence with ourfavourite drink in hand, it is quite clear that many other attendees would simply not have been
there if the conference had been of the traditional kind. This includes participants from developing
countries (it was particularly heart-warming to receive “Thank you” notes from delegates fromsuch countries), participants from far away countries whose travel expenses would probably be
too high to justify participation in a “physical” ECIR, and participants who, although they canin principle afford the money to travel to Europe, would not do this in practice, e.g., because they
do not have a paper in the program, or because work or family commitments would not allow
them to be away for a week.
It was very easy to notice, instead, that the type of participation that the online format
encourages is very different from that of in-presence conferences. When we travel to a “physical”
conference, it is often the case that more than, say, 80% of our time in the day is devoted to theconference (attending sessions, networking with other attendees on or off the venue, etc.). For
an online conference, this is different, and our participation is part-time: we attend a session weare interested in, we skip the next because we need to attend a departmental meeting, we thenattend a keynote, and then we skip the other talks of the day since we need to pick up the kids at
school and go grocery shopping. We realized this would be the case weeks before the event, whenan unusually high number of registered attendees declined our invitations to be session chairs;
because of meetings, family commitments, classes to be taught, and other commitments thatwould simply not be there when attending an in-presence conference. Indeed, this phenomenon
was also clear from the data: while more than 1,100 people registered to attend, the Zoom sessions
were never altogether attended by more than 200 people, a typical number for in-presence ECIRs.
This means that online ECIRs generate a very high number of part-time attendees, instead of amuch smaller number of (almost) full-time attendees.
We also think we learnt some lessons that might be useful for organizers who might be faced
again with the challenge of going completely online. The most important such lesson, organizationwise, is that in-presence conferences and online conferences are very different in terms of the cash
flow they generate. In the case of in-presence conferences, the bulk of expenses is often incurredjust before or just after the event takes place, when bills (e.g., venue hire, catering, buses, printingservices) can usually be paid; at that time, most of the money from registration fees is in already,most of the money from sponsors is too, and there is thus money in the cash for paying the bills.
In the case of online conferences, instead, the most expensive service providers are the online
platforms (in our case: Whova, Zoom, Gather Town), and these want to be paid in full at thetime of booking the service, which is often way before registration fees have started to trickle
in, and before sponsor money has also started to be paid. This generates a problem for thoseorganizers who, due to administrative rules in place at their organizations, are unable to borrowmoney from their own grants for coping with these early expenses. The suggestion for prospective
organizers of online events is not to overlook this problem.

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Let’s meet all at ECIR 2022!

ECIR 2022 will be in beautiful Stavanger, Norway, organized by Krisztian Balog and Kjetil Nørvåg,and will be the northernmost ECIR ever! We are all looking forward to meeting there and enjoying
all the pleasures associated with being all together in a real place, with real people.

References
Djoerd Hiemstra, Marie-Francine Moens, Raffaele Perego, and Fabrizio Sebastiani. Transitioning
the information retrieval literature to a fully open access model. SIGIR Forum, 54(1), 2020.
Djoerd Hiemstra, Marie-Francine Moens, Josiane Mothe, Raffaele Perego, Martin Potthast, andFabrizio Sebastiani, editors. Proceedings of the 43rd European Conference on Information Retrieval Research (ECIR 2021), 2021. Springer Nature, Cham, CH. Lecture Notes in ComputerScience, Volumes 12656 and 12657.

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