BackgroundA decade ago, the Institute for Healthcare Improvement pioneered a quality improvement (QI) campaign, leveraging organizational and personal social networks to disseminate new practices. There have been few rigorous studies of the QI campaign approach.MethodsProject JOINTS (Joining Organizations IN Tackling SSIs) engaged a network of state-based organizations and professionals in a 6-month QI campaign promoting adherence to three new evidence-based practices known to reduce the risk of infection after joint replacement. We conducted a cluster-randomized trial including ten states (five campaign states and five non-campaign states) with 188 hospitals providing joint replacement to Medicare. We measured adherence to the evidence-based practices before and after the campaign using a survey of surgical staff and a difference-in-difference design with multivariable adjustment to compare adherence to each of the relevant practices and an all-or-none composite measure of the three new practices.ResultsIn the campaign states, there were statistically significant increases in adherence to the three new evidence-based practices promoted by the campaign. Compared to the non-campaign states, the relative increase in adherence to the three new practices in the campaign states ranged between 1.9 and 15.9 percentage points, but only one of these changes (pre-operative nasal screening for Staphylococcus aureus carriage and decolonization prior to surgery) was statistically significant (p < 0.05). On the all-or-none composite measure, adherence to all three evidence-based practices increased from 19.6 to 37.9% in the campaign states, but declined slightly in the comparison states, yielding a relative increase of 23 percentage points (p = 0.004). In the non-campaign states, changes in adherence were not statistically significant.ConclusionsWithin 6 months, in a cluster-randomized trial, a multi-state campaign targeting hospitals and professionals involved in surgical care and infection control was associated with an increase in adherence to evidence-based practices that can reduce surgical site infection.Electronic supplementary materialThe online version of this article (doi:10.1186/s13012-017-0579-7) contains supplementary material, which is available to authorized users.