time (hours or days) elapsed from the time a request is made until evaluation is complete, tqueue.
effort (person-hours) to perform the evaluation, Weval.
time (hours or days) elapsed from completion of evaluation to assignment of change order to personnel, teval.
effort (person-hours) required to make the change, Wchange.
time required (hours or days) to make the change, tchange.
errors uncovered during work to make change, Echange.
defects uncovered after change is released to the customer base, Dchange.