If our estimates of task durations are converted by project management software into commitments we aim to meet, and it is difficult to get them done on time [Is Project Management Difficult?], we should simply increase our estimates to be more realistic.
If a task does take longer than “committed,” this “failure” is usually taken personally (by someone). The self-protective, typical response is to increase the estimate the next time this kind of task is planned. This little additional safety should make all the difference. But it doesn’t. It just moves the task end date and pushes the following task’s start date. Perhaps it just needs a bit more. Or maybe a bit more than that. We call this process “experience.”
Here’s an extreme, but not unusual, example of where experience takes us. A Fortune 500 company makes a sidewall panel that takes 8 hours to fabricate and has been doing this every day for years. The panel is planned at 108 days. This is caused by estimate creep and shows up nearly everywhere in various degrees. With 107 days of safety, they still struggle to get it done on time. The sidewall panel is scheduled to a due date at least 108 days out. You don’t suppose they will start working on it tomorrow? Of course not. If they make it too early, they may lose it. And they have.
Even with 107 days of safety, they work to the deadline due date. Did they see this task as having a lot of safety in it? Of course not! How could there be a lot of safety in it? They just barely get it done on time. After 20 years, 108 days is just a number, a standard flow time.
Do we see our projects as having excessive safety? Of course not! We know from experience how long they take.
Copyright © 2011 Skip Reedy
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