### 3PE - why I use three estimates where one might do!

xProcess uses three-point estimating (3PE) for tasks and projects. Why?

Firstly what are the 3 points? Simply the best case, the worst case and the most likely. Just like when you ask how long the repair work will last and you get the reply - "I think it'll take 5 days but if we're lucky it could be 4. Or maybe it'll be much more difficult than I think. It might even take 10 days if there are unexpected difficulties."

In this case the person carrying out the work has given you more information than simply saying it'll probably take 5 days. We have a handle on the anticipated risk associated with this task. The risk associated with the estimate is captured in the gap between best and worst cases. A very wide range shows that he really has no idea how much effort is required for that

The nice thing about giving xProcess 3PE's is that it give you back 3 potential end dates - the 50% end date (you're as likely to finish by then as to overrun), the 75% end date (just a 25% estimated risk of overrrun) and the 95% end date (overrun risk down to just 5%). It give you as a manager or custmoner more information to allow you to handle contingencies. These dates are sensitive to on-going updates to information about resource availability, other task priorities, task dependencies and so on, and if these change the forecast dates change immediately.

The one caution to make about the three-point estimating technique is that it comes up with such authoritative estimates for what we know is a risky and uncertain business. xProcess is only manipulating the estimates that you give it and there are a string of assumptions involved in both the mechanism of making the estimates and the higher mathematics that are used under the covers. My conclusion? Well if you can find a bookie to give you odds of 20 to 1 that the project won't slip its 95% end date I'd take it every time! However the main thing is not just to look at the forecast end date (the 50% date). If the 75% and 95% dates are much later start planning for overruns or marshall your resources to reduce the risks.

### Does your Definition of Done allow known defects?

Is it just me or do you also find it odd that some teams have clauses like this in their definition of done (DoD)?
... the Story will contain defects of level 3 severity or less only ... Of course they don't mean you have to put minor bugs in your code - that really would be mad - but it does mean you can sign the Story off as "Done"if the bugs you discover in it are only minor (like spelling mistakes, graphical misalignment, faults with easy workarounds, etc.). I saw DoDs like this some time ago and was seriously puzzled by the madness of it. I was reminded of it again at a meet-up discussion recently - it's clearly a practice that's not uncommon.

Let's look at the consequences of this policy.

Potentially for every User Story that is signed off as "Done" there could be several additional Defect Stories (of low priority) that will be created. It's possible that finishing a Story (with no additional user requirements) will result in an increase in…

### "Plan of Intent" and "Plan of Record"

Ron Lichty is well known in the Software Engineering community on the West Coast as a practitioner, as a seasoned project manager of many successful ventures and in a number of SIGs and conferences in which he is active. In spite of knowing Ron by correspondence over a long period of time it was only at JavaOne this year that we finally got together and I'm very glad we did.

Ron wrote to me after our meeting:

I told a number of people later at JavaOne, and even later that evening at the Software Engineering Management SIG, about xProcess. It really looks good. A question came up: It's a common technique in large organizations to keep a "Plan of Intent" and a "Plan of Record" - to have two project plans, one for the business partners and boss, one you actually execute to. Any support for that in xProcess?