My general chemistry students rely heavily on proportions as a problem-solving tool, while I tend to use dimensional analysis.  I wonder where this (over)reliance on proportions comes from.  Is this just the way that students coped in their previous science classes? Are proportions more intuitive to students than unit analysis?  Or are high school teachers pushing students to use proportions?

I am divided on whether I should discourage students from their method of choice.  Am I imposing my self-centered problem-solving strategy on already confused students?  Am I out of touch with modern secondary education? I perhaps wouldn’t quibble over methods, except that it seems that my weakest students are the ones who rely most steadfastly on this construction.  And I think that students will find that they are out of their depth when the situation demands more than just a single obvious relationship.