Passive data from a tracking application (or “meter”) installed on participants’ devices to register the URLs visited have great potential for studying people’s online activities. However, given privacy concerns, obtaining cooperation installing a meter can be difficult and lead to selection bias. Therefore, in this article, we address three research questions: (1) To what extent are panelists willing to install a meter? (2) On which devices do they install the meter? (3) How do panelists who installed the meter differ from those who were invited but did not install it? Using data from online non-probability opt-in panels in nine countries, we found that the proportions of panelists installing the meter usually vary from 20% to 42%. Moreover, 20–25% of participants installed the meter on three or more devices. Finally, those who were invited but did not install the meter differ from those who did.

来自参与者设备上安装的跟踪应用程序（或“仪表”）的被动数据，用于注册访问的URL，对于研究人们的在线活动具有巨大的潜力。但是，考虑到隐私问题，获得安装仪表的合作可能很困难，并且会导致选择偏见。因此，在本文中，我们解决了三个研究问题：（1）小组成员愿意在多大程度上安装仪表？（2）他们将仪表安装在哪些设备上？（3）安装仪表的小组成员与受邀但未安装仪表的小组成员有何不同？使用来自9个国家/地区的在线非概率选择小组的数据，我们发现安装仪表的小组成员所占比例通常在20％至42％之间。此外，有20–25％的参与者将仪表安装在三个或更多设备上。最后，