You cannot afford 1% predators

The discussion about sexual assault at conferences has been going on for a few years now. Moral reasoning has been discussed a lot, and I will not repeat that.¹

Here I will give a dispassionate, cold and calculating reason why your community cannot afford to tolerate 1% predators:

If in a community of 50 men and 50 women, one person is a predator who attacks one woman every year and causes her to leave, and every year either a man or a woman joins, the community will be male-only after 100 years.

Even 1% predators is far too much.

To take this apart:

• I assume that interest in the topic is equal between men and women.
• I assume that the community starts out with 50 men and 50 women.
• Now I add a single predator who attacks one woman every year.
• The woman subsequently leaves.
• One new person joins to take her place. Since interest is assumed equal, there’s a 50% chance that it’s a woman and a 50% chance that it’s a man.
• Overall the community therefore loses one woman every second year.
• Within 100 years there will be no single woman left in the community.

Therefore no community can afford to tolerate even one predator per 100 people — regardless of how the predator causes women to leave.

Even 1% predators cause massive structural discrimination. If you tolerate those 1% of people, you lose 50% of your community — and, all moral issues aside, no community should burn half their members for the sake of the 1% who might be predators.

Note that most people in such a community won’t notice the predatory behavior, simply because most of the time they will only interact in smaller subgroups of 5 to 10 people. If in a community of 100 people more than 10 people noticed something odd, that’s a big red flag that there might be a predator in the group who could hurt and drive away half the community if not stopped.

PS: The same goes with the genders reversed: Anyone who makes one person of one specific gender leave every year can effectively render a community single-gender.