How To Start a Grassroots Movement

TL;DR

This study examines how social messaging influences the promotion of a COVID-19 tracing app, finding that receiving messages boosts willingness to send messages, while costs do not impact behavior, suggesting grassroots movements can be cost-effective.

Contribution

It provides empirical evidence on the effects of social messages and cost signals in promoting digital public goods, highlighting the minimal cost needed to initiate grassroots movements.

Findings

Receiving messages increases willingness to send

Cost signals do not affect sending behavior

Grassroots movements can be initiated at low or no cost

Abstract

We study the influence of social messages that promote a digital public good, a COVID-19 tracing app. We vary whether subjects receive a digital message from another subject, and, if so, at what cost it came. Observed maximum willingness to invest in sending varies, from 1 cent up to 20 euros. Does this affect receivers' sending behavior? Willingness to invest in sending increases when previously receiving the message. Yet, cost signals have no impact. Thus, grassroots movements can be started at virtually no cost. App-support matters normatively as non-supporters are supposed to be punished in triage.