The dominant metric in digital video is the almighty completion rate. If the viewer watched my 30 second ad to completion, the brand message and impact was made, right? Well, yes, assuming that the viewer did in fact watch it. But this is an old issue, one that also appears with regular TV. Did the viewer get up and use the restroom or go to the kitchen? Just because an ad was broadcast on the screen doesn't mean a viewer actually saw or heard it. In digital, there are even more ways to miss or avoid the ads, like clicking …