How do you know if you’re making progress towards your objective? Because things either are or they aren’t; things are either done or not done. This chapter describes how to know when things are one or the other.
A couple of multiple choice questions this time:
(a) He had 100 widgets to process, he’s done 90 of them and so there are 10 left. Therefore he must be 90 per cent done.
(b) He had 10 days to do the task and day 9 is about to come to an end. Therefore he must be 90 per cent done.