We’re all very critical of smartphone performance. High end phones are expensive, and ideally they should solve more problems than they create. Also, with each successive generation of phone, we expect a phone to do more and to do those new tasks faster than the previous generation of device.

We can benchmark processors, show off camera improvements, and listen to the audio output, but some aspects of our electronics are more difficult to test. There are also significant differences to account for when looking at devices from different manufacturers, or devices operating on different platforms like Android or iOS. Also, we can sometimes find significant differences between actual raw performance and the user’s perception of that performance.

One of the more subjective metrics someone might use to describe performance is explaining the amount of lag they encounter while using a device. In reading through many of the comments on our videos, we regularly encounter differing opinions as to what qualifies “lag free” performance. Nearly every phone we’ve reviewed has either been condemned for being a laggy mess, or has been praised for offering buttery smooth operation.

Exactly what is lag? How might someone measure or demonstrate that potential problem? Will consumers ever be able to buy a completely lag-free phone?