As detaro wrote: Measure results, not behavior.

Are deadlines missed? Products sub-standard? Then you have something to worry about (and remote work is not a factor).

Are team members regularly having one-on-one meetings with their managers? Are the employees comfortable enough that they can be open with the manager about any blocks or problems encountered? That's a good sign. If you want to count anything, keep track of one-on-ones.

This may be of some use (free reg required). https://www.safaribooksonline.com/library/view/the-remote-wo...