Want a thriving online community? Be sure to have member turnover.

A collaborative study by researchers from the University of Haifa and the New Jersey Institute of Technology reveals which factors can predict the survival or demise of online communities over time.

A sample 282 chat channels all “born” in the same month was used for survival analysis which explored over six months the relationship between the overall user activity in each channel at its inception and the channel’s life expectancy.

Results show that the variable that best predicts the chances of a community to survive is its level of heterogeneity: The greater the member turnover, the higher the chances that the group will sustain itself over time. On the other hand, the number of members and the number of actual message posters do not predict the chances of survival.

Another reliable predictor is the number of messages that are posted between members of an online community. “The present study shows that prediction of an online community’s survival chances cannot be based on quantitative data relating to the size of the group or even to its growth rate alone. A social predictor, on the other hand, can much better predict its chances,” concludes Dr. Daphne Raban of the University of Haifa, who took part in the study.