a Jones,Ray B % a Goldsmith,Lesley % a Williams,Christopher J % a Kamel Boulos,Maged N %+健康、教育和社会学院，普利茅斯大学波特兰维拉斯3号，普利茅斯，PL4 8AA，英国，44 1752586532，ray.jones@plymouth.ac.uk %K集群随机试验%K随机对照试验中的污染%K在线广告%K抑郁%K MoodGym %K生活充实%K谷歌分析%K谷歌Adwords %D 2012 %7 20.06.2012 %9原创论文%J J Med Internet Res %G英文%X背景:谷歌Adwords越来越多地用于招募研究研究和临床服务人员。它们提供了在集群随机对照试验(rct)中从目标控制区招募人员的可能性，但很少有人知道通过位置和对照区进行准确定位广告的可行性。目的:在试点集群随机对照试验中，使用谷歌AdWords进行定位在线干预，以检查控制区域的准确性和污染情况。方法:基于之前对抑郁症的在线认知行为疗法的使用和人口规模，我们有目的地选择了121个英国邮政编码地区中的16个，并将其随机分为三个干预组和一个(不做任何事)控制组。两个干预组包括使用定位的AdWords，我们将其与什么都不做的控制组进行了比较。我们没有提高我们的研究网站的能见度，以正常的网络搜索。点击广告的用户将被引导到我们的项目网站，该网站收集了计算机互联网协议(IP)地址、日期和时间。访客被要求填写他们所在地区的邮政编码，并完成患者健康问卷(抑郁症)。然后，他们被提供了一些在线抑郁症资源的链接。 Google Analytics largely uses IP methods to estimate location, but AdWords uses additional information. We compared locations assessed by (1) Analytics, and (2) as self-identified by users. Results: Ads were shown 300,523 times with 4207 click-throughs. There were few site visits except through AdWord click-throughs. Both methods of location assessment agreed there was little contamination of control areas. According to Analytics, 69.75% (2617/3752) of participants were in intervention areas, only 0% (8/3752) in control areas, but 30.04% (1127/3752) in other areas. However, according to user-stated postcodes, only 20.7% (463/2237) were in intervention areas, 1% (22/2236) in control areas, but 78.31% (1751/2236) in other areas. Both location assessments suggested most leakage from the intervention arms was to nearby postcode areas. Analytics data differed from postcodes reported by participants. Analysis of a subset of 200/2236 records over 10 days comparing IP-estimated location with stated postcode suggested that Google AdWords targeted correctly in just half the cases. Analytics agreed with our assessment that, overall, one-third were wrongly targeted by AdWords. There appeared little evidence that people who bothered to give their postcode did not answer truthfully. Conclusions: Although there is likely to be substantial leakage from the targeted areas, if intervention and control areas are a sufficient distance apart, it is feasible to conduct a cluster RCT using online ads to target British postcode areas without significant contamination. Trial Registration: Clinicaltrials.gov NCT01469689; http://clinicaltrials.gov/ct2/show/NCT01469689 (Archived by WebCite at http://www.webcitation.org/681iro5OU) %M 22718043 %R 10.2196/jmir.1991 %U //www.mybigtv.com/2012/3/e84/ %U https://doi.org/10.2196/jmir.1991 %U http://www.ncbi.nlm.nih.gov/pubmed/22718043