A randomised controlled trial of the Nextdoor Kind Challenge: a study protocol

BACKGROUND: Community interventions are often promoted as a way of reducing loneliness and social isolation in our neighbourhoods. However, those community interventions are rarely examined within rigorous study designs. One strategy that holds the potential to reduce loneliness and can promote health and wellbeing is doing acts of kindness. The current study involves evaluating the impact of kindness acts on loneliness in community-dwelling individuals using an online social networking platform. METHODS: This study is made up of three randomised controlled trials conducted in three countries. Each randomised controlled trial has two arms (intervention vs waitlist control) and is designed to compare the effectiveness of the KIND challenge, which involves doing at least one act of kindness per week within a four-week period. This study will recruit users of an online community, be randomised online, and will be conducted using online assessments. We will first explore the effects of the intervention on the primary outcome of loneliness, followed by secondary outcomes, social isolation, neighbour relationship quality and contact, mental health symptoms, stress, quality of life, and positive affect. Further, we will assess the feasibility, acceptability, and safety of the KIND Challenge. DISCUSSION: This study, designed to evaluate the impact of kindness on the community, will be the first large scale randomised control trial conducted across three countries, Australia, UK, and USA. It will examine the potential of community-led interventions to reduce loneliness, improve social isolation, and promote neighbourhood cohesion, health, and wellbeing, which is especially crucial during the COVID-19 public health crisis. TRIAL REGISTRATION: Clinical Trials Registry. NCT04398472. Registered 21st May 2020. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-021-11489-y.