What little I remember of the definitions are Mild - able to perform at 50% of expected level Moderate - mostly housebound Severe - always housebound, sometimes bedbound Very Severe - always bedbound I've noticed that it is different than Dr. Bell's scale. He puts the 50% level a lot lower on the severity scale. His scale at level 3 states " Moderate to severe symptoms at rest. Severe symptoms with any exercise; overall activity level reduced to 50% of expected. Usually confined to house. Unable to perform any strenuous tasks. Able to perform desk work 23 hours per day, but requires rest periods." This doesn't quite match my experience. My activity level was reduced to a lot less than 50% before I was usually confined to the house. Though I think that a lot of that getting out was stubborness & stupidity on my part. It certainly led to plenty of crashes. I won't go into the rest of Dr. Bell's scale, except to note that I was working a desk job full-time when my activity level was a lot lower than the 70 - 90% shown in his level 6. I have to say that the quality of my work the last year was not very good, and management was not very happy with me. Prior to that, I had bad times and good times and managed to accomplish enough in a year to do a good job. Come to think of it, on a few occasions people wondered why I did (or didn't) do something as I usually did. Sometimes the CFS addled brain works a lot worse than other times. The sad thing is that I didn't necessarily realize that the project I was trying to do wasn't any more difficult than others had been. The difficulty level skyrockets when my brain is mostly zoned out! That last year I felt like management was piling on the work, and didn't understand how they expected me to do so much. Gee, I meant for this to be a simple question, not a long post!