The purpose of this crohns disease activity index (CDAI) calculator is to gauge the progress or lack of progress for people with crohns disease. The reference article says "generally speaking, CDAI scores below 150 indicate a better prognosis than higher scores."
However, since the original study, other researchers use a subjective value of 200 to 250. Therefore, this just reinforces the fact that the purpose is to gauge Your Progress i.e. compare readings from one week to the next to determine if you are getting better or worst. Bottom line is that you need to use the CDAI on a regular basis and view it as a personal gauge. Watch for changes in your score (your gauge).
This indicator does NOT predicts the outcome of the disease. Crohns disease conditions vary for each patient. This calculator is only a gauge of progress i.e. not a prognosis tool!