Marginalized communities online often face disruption from outsiders. When newcomers see this, they can sometimes misunderstand the true norms of a community and decide not to participate. In a two-year project with r/feminism on Reddit, we tested an idea for reducing this collateral damage.

Why do marginalized groups face harassment on Reddit? Identity-based online communities are often easily accessible and welcoming to all participants, as a matter of principle. They often want to encourage empathy, learning, and openness.

Unfortunately, the very features that keep such communities open to newcomers are the ones that keep them open to harassment. Communities like r/feminism are easy targets for coordinated harassment because anyone can join nearly any discussion and because search algorithms enable organized groups to find and disrupt conversations. Rather than limit participation to approved accounts, many communities take this risk because these features also provide pathways to connection for people who are just starting to explore their common identity and values.

Content removals and bans can clean up a problem, but they can’t undo the impact of harassment on bystanders

On Reddit, r/feminism’s goal discusses and promotes “awareness of issues related to equality for women.” Contributors to this 179,000 subscriber community share news and describe personal experiences from feminist perspectives.

Some newcomers to r/feminism feel unwelcome because they experience or observe harassment from people outside the community. When bystanders mistakenly believe that harassment is common, they sometimes choose not to participate. That’s because seeing harassment influences what psychologists call “social norms”— our beliefs about what kind of behavior is typical or expected. In other studies on Reddit, CAT Lab has found that these beliefs affect whether someone chooses to participate at all.

Because seeing online harassment can affect bystander behavior, even communities with strong policies and timely interventions can lose the people who could uphold a flourishing culture of respect in the long-term. Content removals and bans can clean up a problem, but they can’t undo the impact of harassment on bystander perceptions.

supportive messages increased newcomer comments by 20% on average, an effect that persisted across the 10 weeks we collected data

Might people participate more if they understand a community’s actual norms more clearly? To find out, we worked with r/feminism on a study that sent half of newcomers a welcome message, comparing their behavior and survey responses to the rest. This welcome message explained community norms and clarified that harassers were outsiders. 

In this two-year study, we found that messages explaining that harassers were a minority increased newcomer comments by 20% on average, an effect that persisted across the full 10 weeks we collected data (n=1,300; p=0.002). The welcome message also had no detectable side-effects on the number of removed comments or accounts that were banned.

Why feminists stay silent in online feminism discussions 

Why do feminists stay silent on Reddit? To find out, we surveyed r/feminism commenters in April 2018 (n=192, response rate 30%). In their answers, non-feminists admitted that they wanted to disrupt the community. One wrote that “I came here to troll and trigger snowflakes” and another “came to laugh at upset women.” Feminists noted that “it is sometimes difficult in the sub because of disruption by anti-feminists.” Another person wrote that there “seems to be a higher number of anti-feminists expressing disagreement in the comments than feminists.”

r/feminism moderators take quick action to protect the community. In the first quarter of 2020, they banned roughly a thousand commenters a month. But as other reddit communities also experience, popular discussions that draw in newcomers also attract more harassment. Content removals and bans can change a conversation going forward, but they can’t undo the impact of harassment on bystander perceptions.

Frequent harassment can also blur the lines between disruption and good-faith inexperience. Feminists with opinions that differ from the community’s vocal majority report feeling uncomfortable speaking. Several people in our 2018 survey, including women of color, described feeling like “stepping in shells in the comment section,” out of fear of negative reactions from other feminists in discussions about race or differences among feminists.

newcomers who identified as feminist made 29% fewer comments in their first two weeks than non-feminists

These concerns have a real impact on people’s participation in r/feminism. In a follow-up survey, we found that newcomers who identified as feminist made 29% fewer comments in their first two weeks than people who reported being undecided or not feminists (n=163, response rate 25%. p=0.036).

How close do people feel to r/feminism?

To better understand how newcomers understand their relationship with r/feminism, we asked people to rate how close they felt to the community by imagining themselves and their community as circles and picking the pair that most describes their relationship:

Unsurprisingly, non-feminists reported having less overlap with the community than feminists. We were also interested by how many self-identified feminists reported low overlap with the community. Why does this matter? In the ten weeks after their first comment, people who report being one item closer to the r/feminism community contribute 14% more comments on average (p=0.005, controlling for whether the account received a ban).

Updating norms with a community welcome message

If worrying about conflict and harassment made people less likely to contribute to r/feminism, could we increase participation by dispelling misconceptions about the community? We worked with r/feminism moderators to co-design an experiment to find out. After a r/feminism moderator joined our summit at MIT in 2018 and pitched the idea, students from my 2018 Princeton course worked with the subreddit to survey the community and design the study together.

During the study, our software detected if commenters in r/feminism were newcomers—accounts commenting for the first time in six months. If so, the software randomly assigned them to receive a private welcome message or to receive no message at all. After two weeks, the software sent them a follow-up survey (see experiment plan). 

Here’s what the welcome message said:

Hi {username}, thanks for posting to r/feminism!

We see that you’re a new/infrequent contributor, so welcome to our subreddit! We especially value comments that are relevant to women’s issues, are respectful, and are sincere in intention. Please don’t derail the conversation and please follow our community rules.

While our community may not always agree, we want you to know that we value your contributions and your safety. You may sometimes see comments or votes from people who try to undermine the conversation, but they are a minority. If you see a harassing comment, please report it to the moderators by using the “report” button.

We hope you enjoy your time here, learn new perspectives, and feel heard and respected.

— the r/Feminism mod team

Since many people comment in r/feminism, we thought we could reach our goal of 1,666 survey responses in a few months. After starting the study, we noticed that many comments violated Reddit’s overall rules, leading their accounts to be deleted by the platform before our software could include them in the study. We ran the study from July 19, 2018 to May 10, 2019. We then resumed it from February 8, 2020 through April 18th, 2020. Our final sample was 1,300 participants with 320 surveys. The sample was large enough to ask questions about behavioral outcomes but too small to be confident about effects on survey outcomes.

How changing norms about harassment increase newcomer participation rates in r/feminism

To test the effect of the welcome message on rates of newcomer participation over time, we used a negative binomial model. This model produces an “incidence rate ratio” that is a multiplier on the number of comments someone makes. On average, receiving the welcome message caused newcomers to increase the number of their comments by 1.2x, an effect that persisted over their first ten weeks (p=0.002, adjusted for 2 comparisons). 

Since the welcome message increased participation rates, might it also increase the rate of unruly behavior? We did not find any effect on the number of a newcomer’s comments removed by moderators over 10 weeks (p=0.87) or any effect on whether a newcomer account was banned (p=0.32).

Those of you who are interested in the statistics can read the analysis code on github. You will notice that we calculated the average treatment effect differently than specified in the pre-analysis plan. Here’s what we changed:

  • We did not include the number of banned days in the analysis, as planned. It’s a post-treatment variable that could have been influenced by receiving the welcome message. Our updated method is more scientifically reliable and the results are almost identical either way.
  • We used two-stage regression to estimate the effect. This is because due to software errors, several people who were designated to receive a message didn’t receive it. With two-stage regression, we can calculate the effect of actually receiving the message (see Gerber & Green chapter 5).

Do welcome messages influence how close people feel to r/feminism?

We also designed this study to discover if the welcome message influenced how close people felt to r/feminism. With only 320 surveys out of the 1,666 we planned, we’re not confident in our findings on closeness. Unsurprisingly, we failed to find an effect from the welcome message on newcomer reports of how close they were to r/feminism (p=0.667).

What if feminists and non-feminists experienced different effects on reported community closeness? The best way to test this question is to split participants into feminist and non-feminist groups before allocating the welcome message. That wasn’t possible here. Furthermore, since the survey had a 25% response rate, we could only estimate the results among the kind of people who take surveys. Our exploratory survey findings should be taken with a grain of salt, as inspiration for future research.

Among survey-takers, we did not find a difference in feminists’ reported community closeness between message-receivers and those who didn’t receive a message, on average. We did however find a statistically-significant difference for newcomers that reported not being feminists or being unsure. Among those groups, people who received the message reported being 0.8 closer to r/feminism on a scale from 1 to 7 (p=0.016).

Despite this difference in reported closeness to r/feminism among non-feminists, we don’t find a corresponding pattern in participation levels. While self-reported feminists who received the welcome message made more comments on average than those who didn’t (p=0.001), we failed to find a difference in participation among non-feminists.

Can communities undo some effects of harassment by updating bystander’s beliefs about community norms?

Overall, we found that in r/feminism, a community often disrupted by online harassment, sending newcomers a welcome message that explained community norms could increase participation. We don’t know if this intervention might also cause people to report a closer overlap with r/feminism, since we would have needed a larger sample to be sure.

This could be good news in general for marginalized groups that are concerned that visible, coordinated harassment pushes people away. But don’t take our word for it! CAT Lab supports communities on reddit and Wikipedia to do your own studies that test ideas for change. If you’re interested to test this idea in your community, please reach out to Julia Kamin, CAT Lab’s research manager, at <>.

Important note: At the time of posting, the study has not yet been peer reviewed. We wrote this blog post to share initial results with our community partners so they can share feedback that will go into a future academic publication. The final results may change as we improve the analysis or as people choose to opt out of the study.


We are profoundly grateful to everyone who put effort into this study, especially the mods and subscribers of r/feminism who posed the question, co-designed the research, and waited patiently for results while we completed the study. This research was supported through a grant from the Ethics and Governance of Artificial Intelligence Initiative.

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