The Good Enough Point

Dave Shea posts on Understanding Design:

Credibility is the issue here. You don’t walk up to a civic engineer and scribble on his blueprints. You’re more than welcome to voice your concern at a public forum, but it’s up to the engineer to take your concern into consideration, as well as the concerns of everyone else, and figure out the best way to integrate them into an existing workflow, on top of an existing project, without impacting safety and accessibility concerns, while keeping the whole thing on budget. If another well-respected engineer speaks up, you can bet that issue is weighted far higher than the voice of a member of the general public.

I replied:

This aerospace engineer appreciates the reference to my general profession. 🙂 You might have all sorts of great questions as to why this or that in spaceflight construction is or isn’t done, and we’d have a long dialogue. But if we leave it surface, everyone will go, “But of course you’d want to design the crew-compartment of the Shuttle orbiter to be detachable and parachutable!”

Until you take all the design considerations and risks/benefits/costs into perspective, you get to the Good Enough Point and just stop.

I think the Good Enough Point is just not well-understood by the layman. I don’t know how you get to evangelizing it, either.

Dave’s point about credibility is a good one, and it’s one reason I referenced him when I got pissed off last week. People do speak up in town meetings about engineering designs, especially civil engineering ones. The debate is often between someone who just doesn’t want something somewhere&emdash;either for perceived aesthetic, NIMBY, or eminent domain concerns&emdash;and the lead engineer whose team has considered everything [well, except NIMBY, since NIMBY’s are everywhere and should generally be ignored unless they have lots of money or are trial lawyers].

It’s easy for someone like me to criticize design&emdash;my opinions are my own, they’re worth what you pay to read them, and I can self-publish them here. But I’m clearly not a professional, and for me to speak with the authority of a professional would make me come off like a brash, arrogant jerk.


  1. It’s interesting you should post this today. Just this morning in an EE signals and systems class, my professor was discussing how it’s electrically impossible to build a filter that produces a particular amplitude and phase response (at the same time) to a given input signal. This, of course, led into a long-winded, rambling speech about how engineering is different from mathematics or law or accounting in that engineering is about finding answers that are ‘good enough’, because exact answers are impossible to get in most engineering problems. While he, of course, made a much bigger to-do about this than was really necessary (that’s just his style…), he’s absolutely right. If any one concept truly unifies all flavors of engineering, it has to be the concept of “good enough”.

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