Introduction to Software Processes ◾ 189
knowing that all estimates of this kind are burdened by inevitable errors. en Sol
adds these estimates and produces the total for the whole change. In this total, the
errors hopefully compensate each other: e overestimates of some phases compen-
sate for the underestimates of other phases, and the resulting total for the whole
change has a higher accuracy.
A part of planning software change is the prediction of software quality and
introduced bugs. e defect log serves here to indicate by analogy how many bugs
will be introduced by the future changes, how long it will take to fix them, and
how much effort that is going to take. If too many bugs are allowed to accumulate,
the quality of the code deteriorates, ...