It's important to focus on a single topic in order to avoid cognitive overload and learner confusion. (elearningindustry.com)
I take the view that if I receive five or more emails on a single topic in any one day then constituents are telling me their issue is important. (totalpolitics.com)
A variation on the assignment is to invite three or four people to the classroom with different perspectives on a single topic. (edutopia.org)