Over the last three years, I’ve written eleven posts tagged with “Emergence”. In a discussion over the past week of my previous post, I’ve come to the realization that I’ve been misusing that term. In essence, I’ve been conflating emergent architecture with accidental architecture when they’re very different concepts:
The question is intentional vs accidental architecture, not BDUF vs emergent...all architecture involves emergence—
Gene Hughson (@GeneHughson) June 03, 2015
In both cases, aspects of the architecture emerge, but the circumstance under which that occurs is vastly different. When architectural design is intentional, emergence occurs as a result of learning. For example, as multiple contexts are reconciled, challenges will emerge. This learning process will continue over the lifetime of the product. With accidental architecture, emergence occurs via lack of preparation, either through inadequate analysis or perversely, through intentionally ignoring needs that aren’t required for the task at hand (even if those needs are confirmed). With this type of emergence, lack of a clear direction leads to conflicting ad hoc responses. If time is not spent to rework these responses, then system coherence suffers. The fix for the problem of Big Design Up Front (BDUF) is appropriate design, not absence of design.
James Coplien, in his recent post “Procrastination”, takes issue with the idea of purposeful ignorance:
There is a catch phrase for it which we’ll examine in a moment: “defer decisions to the last responsible moment.” The agile folks add an interesting twist (with a grain of truth) that the later one defers a decision, the more information there will be on which to base the decision.
Alarmingly, this agile posture is used either as an excuse or as an admonition to temper up-front planning. The attitude perhaps arose as a rationalisation against the planning fanaticism of 1980s methodologies. It’s true that time uncovers more insight, but the march of time also opens the door both to entropy and “progress.” Both constrain options. And to add our own twist, acting early allows more time for feedback and course correction. A stitch in time saves nine. If you’re on a journey and you wait until the end to make course corrections, when you’re 40% off-course, it takes longer to remedy than if you adjust your path from the beginning. Procrastination is the thief of time.
Rebecca Wirfs-Brock has also blogged on feeling “discomfort” and “stress” when making decisions at the last responsible moment. That stress is significant, given study findings she quoted:
Giora Keinan, in a 1987 Journal of Personal and Social Psychology article, reports on a study that examined whether “deficient decision making” under stress was largely due to not systematically considering all relevant alternatives. He exposed college student test subjects to “controllable stress”, “uncontrollable stress”, or no stress, and measured how it affected their ability to solve interactive decision problems. In a nutshell being stressed didn’t affect their overall performance. However, those who were exposed to stress of any kind tended to offer solutions before they considered all available alternatives. And they did not systematically examine the alternatives.
Admittedly, the test subjects were college students doing word analogy puzzles. And the uncontrolled stress was the threat of a small random electric shock….but still…the study demonstrated that once you think you have a reasonable answer, you jump to it more quickly under stress.
It should be noted that although this study didn’t show a drop in performance due to stress, the problems involved were more black and white than design decisions which are best fit type problems. Failure to “systematically examine the alternatives” and the tendency to “offer solutions before they considered all available alternatives” should be considered red flags.
Coplien’s connection of design and planning is significant. Merriam-Webster defines “design” as a form of planning (and the reverse works as well if you consider organizations to be social systems). A tweet from J. B. Rainsberger illustrates an extremely important point about planning (and by extension, design):
Plan all you want. What you do in the face of unexpected results matters much, much more. #agile—
☕ J. B. Rainsberger (@jbrains) June 05, 2015
In my opinion, a response to “unexpected results” is more likely to be effective if you have conducted the systematic examination of the alternatives beforehand when the stress that leads you to jump to a solution without considering all available alternatives is absent. What needs to be avoided is failing to ensure that the plan/design aligns with the context. This type of intentional planning/design can provide resilience for systems by taking future needs and foreseeable issues into account, giving you options for when the context changes. Even if those needs are not implemented, you can avoid constraints that would make dealing with them when they arise more difficult. Likewise, having options in place for dealing with likely issues can make the difference between a brief problem and a prolonged outage. YAGNI is only a virtue when you really aren’t going to need it.
As Ruth Malan has noted, architectural design involves shaping:
ruth malan (@ruthmalan) June 08, 2015
Would you expect that shaping to result in something coherent if it was merely a collection of disconnected tactical responses?