Shallow depth of field (DOF) is a physical effect due to sensor size, focal length and object distance. If you read up about the basics of DOF you will see these 3 parameters.
Bokeh is a quality parameter, describing how pleasing the out of focus area is to the eye of the beholder. It is largely depending on the built of the lens (aperture blades, lens elements). Some lenses have a very pleasing bokeh, others don't - but having exactly the same DOF. In addition, no lens can turn an ugly and messy background into something pleasing and suitable for portrait. That's the photographer's job.
That's what happens when people who know 70% (but think they know 99%) start sharing their "knowledge" with others on a forum... :bsmilie:
Octarine has already corrected your myth about shallow dof = creamy bokeh
Be your first and sharpest critic. Does the blurred background really emphasize the object (which must be sharp then of course) or is it just a blur mess? There are nice examples here in CS where the background is simple, clear and nicely blurred. Other examples show a wild mix of colours, sometimes even brighter than the foreground, screaming for attention.
Bokeh alone is not the point, it's a part of the overall picture composition.
IIRC, bokeh CAN be calculated, or 'measured' since it is dependent on the laws of physics.
What is difficult though, is transposing the calculations to an 'easy to understand/use chart' or 'reference' that various lens designers/manufacturers and end-user parties may agree on, because you're trying to translate hard maths into a set of visual values, which are usually very subjective.
Warning! Trying to do the math may result in massive headaches! :bsmilie:
TS can also look at http://www.rickdenney.com/bokeh_test.htm to see the difference between good bokeh and not-so-good bokeh between lenses at the similar subject distances, focal lengths and aperture values.