## Main

Conferences fulfil a range of needs by facilitating dissemination of ideas, initiating collaborative relationships and providing education, training and career opportunities. Traditional in-person conferences (IPCs) have filled this role for centuries1 and these events cut across all sectors: academia, industry and government. However, this format has been criticized as outdated and detrimental to the environment2,3,4. More recently, emerging evidence is also connecting this modality to social sustainability issues as well, notably poor retention of a diverse workforce. In this context, the two dominant contributors are the intrinsic power-imbalance in the workplace and an imbalance in home-life responsibilities5,6.

Over the past two decades, the creation and sustainment of a diverse, equitable and inclusive (DEI) work environment in the scientific and engineering community has not kept pace with many other fields. In part, this can be attributed to career expectations revolving around conference travel and participation. Participation in conferences can be cost prohibitive for many, as the cumulative expenses can be thousands of US dollars per person. International travel creates additional barriers7 which are exacerbated by the frequent changes in document requirements and lengthy delays in obtaining visas. These financial and documentation barriers can also dissuade scientists that have difficulty securing funding to cover conference costs such as students, postdoctoral researchers or scientists from historically under-represented institutions. These factors can also exclude participants from countries that do not have very high research activity, such as nations that are not in the top ten research countries as defined by the Nature Index (NI; ref. 8), NI > 10.

However, even for those researchers who are able to travel, the time away from home necessitated by work-related travel is intrinsically exclusionary to care-givers, who are primarily women3,7,9. Yet, given how important conference attendance is to career advancement, this community is frequently faced with the decision of choosing between work and family. Lastly, despite conference organizers’ attempts to solve accessibility concerns of the disabled community, many conferences still fall short of providing an equitable experience.

The recent surge in virtual events is forcing the scientific community to re-evaluate its long-held position against virtual conferences (VCs). The initial anecdotal evidence indicated that VCs enabled a more diverse population to participate. But a quantitative analysis of the impact on DEI challenges has yet to be performed. Such analysis is critical to make decisions regarding the format of future events, potentially resulting in a paradigm shift in the field. Here, we evaluate several metrics, including cost, carbon footprint, impact of conference format and attendee demographics. We collected historical data from three IPCs based in the United States, of varying sizes and disciplines within science, technology, engineering and mathematics (STEM). These results were compared to the same three conferences after they transitioned to a VC format in 2020. These scientific conferences were among the early conferences to transition online in response to the COVID-19 pandemic and were chosen to investigate the impact of an abrupt transition from historically IPCs to a new virtual format.

The historically IPCs-turned-VCs analysed here are the annual International Conferences on Learning Representations (ICLR), the American Astronomical Society (AAS) and the North American Membrane Society (NAMS) conferences. Also analysed here are several conference series that were originally designed for the VC environment, including the Photonics Online Meetups (POM 1, January 2020; POM 2, June 2020) and the International Water Association (IWA) Biofilms conference. These conferences span five fields of science and engineering and range from small- to large-scale events. All have international audiences.

We focused our analysis on the environmental, social and economic costs of VCs versus IPCs and accompanying demographic impacts (global participation), participation from women, early career researchers and scientists from under-represented institutions. We also assessed the challenges and benefits of the VC format.

## Results

### Demographic impact

The elimination of the travel and cost burdens realized with the VC format resulted in a large increase in attendance at all events (Fig. 1). The increase in attendance was particularly pronounced for international attendees. We propose that this trend may be related to the substantial decrease in costs as compared to IPCs as described below.

### Gender make up of STEM researchers from conference attendee’s countries

Country-specific percentage of women data are taken from ‘female researchers as a percentage of total researchers (full-time equivalents)—natural sciences and engineering (subtotal)’ published as ref. 26 with the exception of the United States which is not included in that dataset. US percentage of women is derived from women as a percentage of MSc and PhD graduates employed in science and engineering occupations27. Overall percentage of women in STEM for the countries represented in the conference delegations was calculated with percentage values from each country represented at the conference, weighted by the number of attendees from each country.

### Reporting Summary

Further information on research design is available in the Nature Research Reporting Summary linked to this article.