Message that trolls are present but outnumbered

Make new users more comfortable in community and more resilient to trolling



Message that trolls are present but outnumbered

Share This Intervention

Back To Top


What It Is

This simple intervention is a message for new users of a platform or new members of an online community.

It has three key elements:

  1. A link to what is considered trolling in the community or platform
  2. A warning that users will sometimes see trolling, but that non-trolls outnumber the trolls
  3. Instructions for how to handle trolls

When To Use It

This can appear as an automated comment to a new user's post, as an automated personal message, or as an interstitial upon entry.

What Is Its Intended Impact

This intervention has been shown to:

  1. Increase retention of users who join the community in good faith. Those know beforehand that trolls are present and have the tools to deal with them are less likely to be scared away from the platform by harassment. (CAT Lab 2020)
  2. Increase proportion of good-faith users relative to those who join as provocateurs, &c. Where this intervention was used, the increase in retention was limited to those who actively identified with the mission of the community - retention did not increase among those revealed not to be joining in good faith. (CAT Lab 2020)

How We Know It Works

Why It Might Work

Researchers at Cornell's Citizen and Technology Lab conducted a two-year project with r/feminism on Reddit to test an idea for reducing harassment. After presenting 1,300 users with this intervention, they found that messages explaining that harassers were a minority increased newcomer comments by 20% on average. This effect persisted across the full 10-week period of the experiment.

Why It Matters

This could be useful for reassuring and empowering marginalized voices who would otherwise be silenced by hostility. It may also help with polarization, as it helps newcomers and outsiders to an online community more accurately gauge hostile users as being the minority that they are, rather than seeing them as representative of the entire community and treating that community accordingly.

Special Considerations


No items found.

Our Confidence Rating


Convincing Grades are for interventions with peer-reviewed evidence. They have yet to face attempted replication. This is our penultimate grade.

in the wild

This intervention has precedence, and exists, or has at one time or another, existed in the wild.


Intervention Specific Research

Preventing harassment and increasing group participation through social norms in 2,190 online science discussions.


J. Nathan Matias

Date of Publication

April 29, 2019

Sample Size(s) (N-values)



Natl. Acad. Sci. U.S.A

Entry Type

Research Article or Manuscript

Publication Status

Peer Reviewed

Study Design


Online Impact


APA Citation

Preventing harassment and increasing group participation through social norms in 2,190 online science discussions J. Nathan Matias, Proceedings of the National Academy of Sciences Apr 2019, 201813486; DOI: 10.1073/pnas.1813486116


There's more to learn about this intervention. Want to help?

Do you think this intervention could have more benefits, unacknowledged drawbacks, or other inaccuracies that we've neglected to mention here?

We always welcome more evidence and rigorous research to back up, debunk, or augment what we know.

If you want to be a part of that effort, we'd love to have your help!

Email us

Further Reading

Back to Prosocial Design Library