> The officers themselves also dropped off cards to local residents containing similar information…The team found that residents of the developments that had received the intervention believed it more likely that local officers would find out about illegal activity than residents of the control areas (though there was no significant effect on residents’ perceptions of how well police officers knew them).

This seems like a leap—couldn’t these folks instead be thinking “oh the police stopped by my building, they are paying attention”? The real study is behind a paywall so I’m curious if this was controlled for.