To redirect or not redirect, Is that the question? I actually think it is more about whose job is it to do the redirection.
I had an email exchange with a 3rd grade teacher. She made a comment at the end of the email that stuck out for me. She wrote: " he can get quite distracted on one thing (whether that's another student, or scratching deep dark lines with his pencil onto his assignment).He will stay in this distraction until verbally redirected."
I see this ALL the time with my clients. It can be so disruptive to learning but it can be worked through over time. Because ALL people get distracted, the challenge is not necessarily that a child needs to focus on work or whatever she is "supposed" to be doing without ever taking a break or zoning out. That is unrealistic for anyone. We all get off track at times but we can get ourselves back to work. The challenge for some kids is that it is always someone else who redirects them. If they can learn to recognize that they are off task and get back on track on their own, they will be starting down the path that is much more sustainable for long term learning and growth.
I have two ways that I use pretty successfully to increase awareness with clients. It is best practiced in non-stressful situations, so times when a specific outcome in a specific timeframe is not of the essence. Strategy #1 is to set a timer on a phone or watch when the attention wanders. Hold the timer near them so they can see that it is clicking through the time. I have an iphone and the stopwatch function is quite big and clear and if I start it and hold the phone within the child's field of vision, I have been surprised with how quickly they are curious about why I am doing that. When they ask or shift their attention to the stopwatch, I just report, "We were doing math but then you have been doing X for Y amount of time." What I have found, to a child, is that they will get back to the math on their own with that information. It is frequently that they are surprised that they were off track for so long.
Strategy #2 is more verbal but is helpful if you don't have a stopwatch. When the child becomes distracted, simply repeat what you see them doing that is not the thing they are supposed to be doing. "I see you are doodling." Pause. "I see you are making lines on your math paper." Pause. "I see you made a big pile of eraser dust." Pause. And you could intersperse statements of what you had expected them to be doing such as, "You are ready for #5," or "I see you finished all the addition and you seem ready for the subtraction."
Both of these strategies bring the child’s awareness to what they are doing in the moment but do not give them an exact path back to what they "should" be doing. The reason I don't recommend a specific direction of "Do problem #5 please," is that these directions doesn't foster thinking and planning that leads to independence. Instead, that direction is more likely to lead to compliance or non-compliance. The child can choose to listen to your direction or not. By making statements of fact based on your observations, you are giving them the context to make their own decision of what to do and plan for how to do it.