Using google adwords for international multilingual recruitment to health research websites

Background: google adwords,the placement of sponsored links in google search results,is a potent method of recruitment to internet-based health studies and interventions. however,the performance of google adwords varies considerably depending on the language and the location of the target audience. objective: our goal was to describe differences in adwords performance when recruiting participants to the same study conducted in four languages and to determine whether adwords campaigns can be optimized in order to increase recruitment while decreasing costs. methods: google adwords were used to recruit participants to the mood screener,a multilingual online depression screening tool available in english,russian,spanish,and chinese. two distinct recruitment periods are described: (1) unmanaged