onferences 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 centuries 1 and these events cut across all sectors: academia, industry and government. However, this format has been criticized as outdated and detrimental to the environment 2-4 . 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 responsibilities 5,6 .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 barriers 7 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 women 3,7,9 .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, engine...