[billswift]

>The size difference is basically the number of people who dropped out.

Not hardly. There are a lot of people in other disciplines that take lower level computer science courses. Quite possibly more than are enrolled in comp sci itself.

[jerf]

My school separated comp sci major and non-major tracks. Very few were in the intro comp sci classes who were not intending to be majors for me. YMMV. At any rate the point is there's a very high dropout rate in computer science. Many more switch out than switch in.