Preventing and detecting fraud in web-based surveys with in-person recruitment: lessons for data integrity

Abstract Background Fraud is a well-documented threat to data integrity in online research. However, little research has examined fraud risk in studies that rely on in-person recruitment but collect data online, particularly when preserving participant anonymity is necessary. The purpose of this study was to describe and evaluate fraud prevention and detection strategies in the context of an anonymous, web-based survey that relied on in-person, targeted recruitment. Methods We evaluated fraud in a cross-sectional survey examining the experiences, needs, and barriers faced by families living in hotels in DeKalb County, Georgia. Eligibility criteria included being 18 years of age or older, currently residing in a hotel in DeKalb County, and living with at least one child under 18 years of age. Eligible participants were recruited through door-to-door outreach and received a flyer containing a survey link. Each survey entry was assessed for potential fraud using a standardized protocol comprising ten criteria and were classified as valid, potentially fraudulent, or fraudulent. Descriptive analyses were performed to summarize violations of fraud detection criteria. Results Among 246 completed survey entries, 11 (4.5%) were initially categorized as fraudulent and 14 (5.7%) were categorized as potentially fraudulent. Duplicate IP address was the most frequently violated criterion (59.7%). However, 85.9% of these entries were ultimately classified as valid, indicating a high false-positive rate for this criterion. Other frequently violated criteria included survey duration (18.8%), time of survey submission (17.1%), and a Qualtrics duplicate flag (10.2%). Fewer than 5% of entries were flagged for email address concerns, survey response patterns, recruitment method, hotel response, demographic information, or eligibility alignment. Conclusions These findings demonstrate that in-person recruitment does not eliminate fraud risk in online research. Fraud prevention and detection protocols should therefore be implemented proactively, even when recruitment is targeted and survey links are not publicly distributed. Rigorous approaches require advance planning, including allocating staff time for review and participant follow-up, and explicitly documenting procedures in ethics board applications and informed consent materials.