Geeks With Blogs

@UMLGuy
  • UMLGuy @LeeHate are you still selling art? I would like to license Vodun Bokor for book/ebook cover. It's incredible! You're very talented. about 832 days ago
  • UMLGuy @kzoomoo Indeed. You know 2 of my influences. Characters have multiple influences, but Father and Daughter partly inspired by your family. about 1219 days ago
  • UMLGuy @SteveAndrews That is awesome news, man! You worked hard for that. about 1219 days ago
  • UMLGuy The Night We Flushed the Old Town in Digital SF V2. Kindle: http://t.co/8cVA6zw It's about ecological disaster. And beer. about 1234 days ago
  • UMLGuy @kzoomoo Sounds like a very happy birthday! Your kids are great, as always. about 1369 days ago
  • UMLGuy @julielerman You're in Bangalore and Bali... and you need cheap tickets to feel lucky? I would call that great fortune in itself. about 1369 days ago
  • UMLGuy So weird watching Dr. Gregory House M.D. play Bertie Wooster. Same facial expressions convey completely different meanings. about 1369 days ago

News LoungeWare is now available. The UML Guy T-Shirt
Ulterior Motive Lounge UML Comics and more from Martin L. Shoemaker (The UML Guy),
Offering UML Instruction and Consulting for your projects and teams.

There’s an old joke about an engineer called out of retirement by a company in trouble: their most vital machine has stopped working, and nothing they have tried will get it started again. The old engineer looks at the machine, studies it for a few minutes from different angles, and flips a switch. Presto! The machine starts to work, humming along like it never had a problem. The engineer hands the owner a bill for $10,000; and the owner says, “For flipping a switch? That’s outrageous! I’m not paying until I see an itemized bill.” So the engineer takes back the bill and writes on the back, “Flipping the switch: $1. Knowing which switch to flip: $9,999.”

Unfortunately, I find that a lot of patterns work is like that: if you know which pattern to apply, the work is (relatively) easy; but if you don’t know the patterns, you don’t know when to apply them. Like the company owner in the joke, there’s a switch out there, but you don’t know to flip it.

Well, the best way to learn patterns (like most things) is by experience. I can’t give you experience in a blog, but I can give you Diagnostic checklists that summarize experience. Patterns may also have Verification checklists, and Antipatterns may have Correction checklists. Some Patterns may have multiple Verification checklists. For example, Pattern 10. Brainstorming session has three checklists: one for preparing a Brainstorming session, a second for assessing the success of the session, and a third for summarizing the results of the session.

N/A: Your Defense Against Obsession

As I’ll discuss under Antipattern 26. Obsessive Compulsive Template Disorder (OCTD), it’s easy for bureaucracies to turn templates and checklists into must-do tools for “managing” a process, even when those templates or checklists don’t apply. This is a form of what Steve McConnell describes as “cargo cult software engineering”: going through the motions without understanding why, and without actually getting the benefits (Professional Software Development: Shorter Schedules, Higher Quality Products, More Successful Projects, Enhanced Careers, pp. 23-28.). These checklists aren’t goals in themselves; they’re tools to help you in your goal of more complete and useful requirements analysis.

The best defense against OCTD is N/A: Not Applicable. Whenever a line item in these checklists doesn’t apply to your project, mark it N/A. Then give your project 0 points or full points for that item, whichever you think is best.

Of course, it’s easy to take this too far, and mark everything as N/A. Perfection! You get 100%, right? Wrong. So when you do mark an item as N/A, also explain why it doesn’t apply to your project. If you can’t explain why, you can’t claim N/A.

Scoring the Checklists

Each checklist is scored on a 0 to 100 scale.

Diagnostic Checklists

Diagnostic Checklists are scored as follows:

0-20 Insignificant. This Pattern won’t help you much, or you have little risk of this Antipattern. Only worry about this Pattern or Antipattern if your project is mission-critical. Monetarily, this will cost you more than you’ll gain; but you could still mitigate non-monetary risks.

21-50 Minor. This Pattern may help you, or you have some risk of this Antipattern; but you probably have higher priority Patterns and Antipatterns to address. Worry about this Pattern or Antipattern if your organization is highly risk averse. Monetarily, this may cost you more than you’ll gain; but you could still minimize risks.

51-80 Significant. This Pattern will help you, or you have significant risk of this Antipattern. If you’re not addressing this Pattern or Antipattern in some fashion, that should be an item on your risk assessment.

81-90 Major. This Pattern should be a primary element of your requirements process, or this Antipattern is a primary risk for your project. If you’re not addressing this Pattern or Antipattern in some fashion, that should be a top item on your risk assessment.

91-100 Critical. This Pattern will be a critical element in the success or failure of your project; or this Antipattern is a critical risk for your project. If you’re not addressing this Pattern or Antipattern in some fashion, that should be an immediate item on your risk assessment.

Verification and Correction Checklists

Verification and Correction checklists are scored as follows:

0-20 Misleading. What you think you know regarding this Pattern or Antipattern is more wrong than right. If you proceed based on this score, expect to throw away and rework as much as 100% of your work.

21-50 High Risk. You’re starting to learn about this Pattern or Antipattern; but much of what you know is incomplete or incorrect. If you proceed based on this score, expect to throw away and rework as much as 50% of your work.

51-80 Agile. Agile processes are based on a conviction that many requirements can only be known through delivering and assessing code. Agile proponents point to examples and experience that show that requirements identified too completely in advance can be time-consuming and misleading. So an Agile team should aim for a middle-ground of knowledge: complete enough to lead to code, not so complete that they never get answers.

81-95 Optimal. Your knowledge regarding this Pattern or Antipattern is good enough for most teams to proceed. As Steve McConnell has documented (Professional Software Development: Shorter Schedules, Higher Quality Products, More Successful Projects, Enhanced Careers, pp. 15-16.), teams that focus on quality and defect reduction actually reduce costs and schedule by doing so, up to a point. After that point, even better knowledge costs more money and schedule, and is only appropriate for mission-critical projects. Most teams should proceed based on optimal knowledge.

96-100 Minimal Risk. Your knowledge regarding this Pattern or Antipattern is good enough for mission critical teams to proceed.

Point Lists

Point Lists apply to your entire requirements process. Each checked item scores a certain number of points. Check each item that applies, and sum the point points to get a score from 0 to 100.

Sample Point List: Feeding the Dog

50 You have dog food; or you have table scraps.

30 You have the dog.

20 The dog is hungry.

____ Total

In some cases, the list potentially sums to greater than 100; but 100 is the maximum score in any case. For example, the Verification Checklist for Pattern 6, Trained Analysts, provides 100 points for dedicated analysts and 50 points for developers trained in analysis techniques; but a team with both still scores only 100 points.

Percentage Lists

Percentage Lists apply to your set of requirements, or perhaps to a set of one kind of requirement. Each requirement item is scored a 1 if it meets the criteria, or a 0 if it doesn’t (no partial credit allowed). Your score is the percentage of requirement items that scored 1 vs. the total number of items.

Sample Percentage List: Feeding the Dogs

%__ Percentage of all dogs which have been fed.

Partial Percentage Lists

Partial Percentage Lists are Percentage Lists that allow for partial points. Each requirement item receives some number of points based on various questions; and then you determine the percentages that meet different point scores. Full points count for full percentage; but the percentage of partial points are divided to yield a lower score. The final score is the sum of these adjusted percentages.

Sample Partial Percentage List: Caring for the Dogs

1 The dog is fed.

1 The dog is groomed.

1 The dog is exercised.

%__ Percentage of dogs which score 3 out of 3.

%__/2 Percentage of dogs which score 2 out of 3.

%____ Total

Posted on Sunday, February 1, 2009 1:43 PM Requirements Patterns and Antipatterns | Back to top


Comments on this post: Requirements Patterns and Antipatterns: Checklists

No comments posted yet.
Your comment:
 (will show your gravatar)


Copyright © Martin L. Shoemaker | Powered by: GeeksWithBlogs.net | Join free