Despite standards, viewability measurements done by "black box" vendors are not reliable because they cannot be independently verified for accuracy. Marketers should DIY (do it yourself) using standard browser javascript code to double check if the measurements from the vendors are even close. With published estimates of viewability in the 60 - 80% range, it is likely very far off. Look at the directly measured data in the following charts and see for yourself what correctly measured viewability looks like.