DRM - Daniel’s Random Mutterings

A while ago, I had a chance to spend a week and a half in Palo Alto on business. On the weekend, I took my rental car and went for a drive around California to take in a few of the sights. One of the attractions I visited was the Winchester Mystery House south of San Jose.

The story of the WMH

The story behind the house (as I remember it) is this. Sarah Winchester — widow of the guy who invented the Winchester Rifle — was a bit batty. That’s because she lived in America; had she lived in England, she would merely have been eccentric. She lived in this mansion and had all the wealth her late husband had accumulated due to rather satisfying sales of his patented rifle (you know the one — I think Wyatt Earp uses it in one of the movies about the OK Corral).
Somehow, the good widow had gotten it into her head that she needed to placate the souls of those killed by her husband’s invention. So every night she held a séance and listened to the spirits, who would give her visions of what she should add to her house. As long as she kept on building the mansion, she would be safe from the spirits’ wrath. So for 38 years she kept on adding to the mansion, keeping all the builders in the area pretty busy. She added towers, outbuildings, new wings, whole new floors, lots and lots of windows (some of them in interior walls, not actually looking outside), fireplaces, and more. In order to confuse the spirits (and - quite probably - a few builders along the way), she added staircases that go around in circles, doors that are backed by brick wall and don’t actually lead anywhere, staircases that go up to the ceiling and just end there, and several other quaint but not very useful building features. Somehow, I don’t think she was interested in a feature in Better Homes and Gardens magazine. Since she was, for the time, spectacularly wealthy, none of this construction was done on the cheap. She imported windows and material from France, added marble statues and other works of art. She added gas lighting and indoor plumbing. The large staterooms have beautiful wood flooring and divine fireplaces.
She kept up this construction project right up until her death. The result is simply spectacular. A sprawling mansion, covering a large area. There are fascinating guided tours through the grounds and the mansion. If you haven’t been there yet, and are in the area, visit it. It’s a really cool place.

WMH IT Projects

Only recently did I realize that in IT projects, many of us are spending our time building the software equivalent of the Winchester Mystery House. Projects start out with what appears to be a clear idea of what is to be accomplished and what it should look and behave like. Somewhere along the way, though, the spirits demand their due — the spirits in this case being the project owner, or the customers — and they exert their spine-chillingly terrible control over our life and work: Requirements Creep.
We think we know where we’re headed, and think we know what we’re doing. When one day we hold this séance. Sorry. Milestone Review meeting. And the vengeful spirits come out of the woodwork and give us new visions. “This is great. Now, if only it also did this…”. “Somehow, that doesn’t look like what I wanted. Maybe if you could add…”. “Ummm… yeah, I know I said I wanted that. But now that I’m seeing it, I realize that that also influences this other thing over here. Can you remove this new feature and add in the following change?”. And suddenly we find ourselves adding staircases that go nowhere, building towers and buttresses onto what was supposed to be a garage, putting brick walls behind doors in order to confuse people, and so on. Oh, yeah — of course the spirits tell us to use only the best materials (”This should be done using XML. Oh, and can you add an SOA adapter by Friday?”) and most impressive components, otherwise it just won’t look right and the spirits will take revenge. Sorry — I meant The Customer is not going to sign off on it.

What can you do?

A lot has been written about scope creep, requirements creep, requirements management in projects. What it all comes down to is: Don’t start building the Winchester Mystery House.

Sometimes, revisiting and revising requirements is (or appears) unavoidable. Time passes. People change their minds. New technologies allow new solutions to a problem. New problems necessitate new solutions. Sometimes, the customer realizes he was just plain wrong.

Agile software development methodologies, such as SCRUM, have answers to this requirements creep: Work iteratively. Involve the customer. Involve the team. Work in time-boxed increments. Have clear and achievable milestones. Don’t change direction in the middle of an iteration.

Staying in my WMH simile, I would add a few points. A sure way towards desaster when faced with scope creep is leaving that staircase in place which goes halfway up to the ceiling and then just ends. Don’t be afraid to tear down parts of what you built if you realize that you headed off in a wrong direction. If you started building a garage and the customer now realizes he wanted an observation tower, get rid of the garage. Regroup, redesign, refactor. If you’re using version control (and you are, aren’t you?), the worst that can happen after you’ve chucked something out is that the customer will change his mind yet again and you need to check out a solution you previously ripped out and put it back in. But don’t just add and patch onto stuff just because it was there and somehow you thought you could fiddle your new requirements around it. It’s not that bad to change your plan. Just make sure you have one at each point in time and make sure it’s consistent and correct, based on what you know at that moment.

Oh, and you need to know when to stop. Where to draw the line. The spirits may appear frightening and vengeful, but they only are as long as you keep giving in to them. At some point in time you simply need to be able to see through the posturing and threats and realize that what’s being given to you as a vision in the séance is not only silly or dangerous (or both) but way out of scope and cannot (and should not) be added.

Otherwise, you’ll have to start thinking about hiring tour guides and giving groups of open-mouthed tourists guided tours through your application. The problem is: they’d enjoy looking at it, and they might tell their friends about it. But they wouldn’t want to live in it.

Tags: requirements; scope; scope creep;architecture.

Bookmark on del.icio.us
Add this post to digg.com
Bookmark on reddit.com

This entry was posted on Monday, March 5th, 2007 and is filed under Industry. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.