I don't get it. They used a metric of looking at different screens as a lack of focus tool, and yet I've just had a nice 2 hour long session of developing a script, where I kept glancing between the script and the output on 2 monitors to see if I had fixed it. By their metric I was not focused, and yet I was just telling my colleague I had a great 2 hour long focused session
They probably meant 'window', i.e. what application had their focus. That's probably also not a very good metric though, given that developers will often flip between editors, terminals and browsers rapidly. It compares with 2004, although it doesn't specify in what area; I'm sure that single-application focus is also highly dependent on the area of work and the software used. Some people can do all their work in one application, others need half a dozen or more.
They probably mean task-specific application window, not actual computer screen as many people even today just have a single monitor. Also I doubt they used software developers for test subjects.
