Goodness is fundamentally a subjective attribute. Trying to measure it objectively is attempting alchemy. You cannot make the subjective out of the objective - you will always have smuggled subjectivity in somehow.

Suppose I say that good code should have the lowest number of curly braces, or the lowest number of subroutines, or the flattest or deepest object hierarchy. A measure being objective doesn't make it good. So why is test coverage good?

In fact, every single one of the metrics proposed in the parent post is something I have seen gamed to the point of maladaptivness.

* execution performance time
- So frequently overly focused on that you can find google hits for "Premature optimization is the root of all evil." I have seen developers spend hours or days saving (sometimes imagined!) run time, where all the time they saved over the life of the product wouldn't add up to the time spent. Extreme pursuit of performance leads to code that is hard to work on - who cares about those milliseconds when critical new features take months to write, or are even impossible?

* build time -
It is very easy to diminish build time by destroying critical architecture. I have done it myself. :)

* regression frequency -
Insisting on only making very safe changes is how you wind up spending six weeks lobbying change control boards for one line of code.

*defect quantity -
In environments that actually track this, people merge issues into a single "fix what's wrong" ticket, degrading the utility of the ticket system. Defect granularity is not actually obvious!

* code size -
Obfuscated X contest entries are often very compact, and people who obsess on saving lines and characters can wind up leaning towards that style.

* dependency quantity -
Leads to attempts to homebrew encryption.

* test automation coverage -
Automated testing ossifies design and architecture, which can paralyze, e.g., an experimental prototype. Full coverage is also costly - time and energy spent maintaining pointless tests can come at the expense of mitigating more realistic risks. I realize I depart from prevailing wisdom in this, but there are times and places when automated testing is simply inappropriate.

* test automation execution duration -
Sometimes the right way to write a test is slow.

I'm not disagreeing that these are generally good things to strive for. They are! I'm saying that if you think these things define goodness, each one can lead you to a cursed place. (I hasten to add that there are times when a metric really does define goodness - sometimes you need speed or reliability or whatever, at any cost. Recognizing that circumstance and its limits - "any cost" does not generally mean any cost - is subjective.) Goodness is subjective, and while objective measures can help you assess it, such measures cannot define it - when and how you use which measures, and when you think they've gone off the rails, is itself a judgement call.

I once inherited a system that was both essential for business operations and a thorn in everyone's side. The guy I inherited it from (and the guy he inherited it from) had taken over a year to learn how to use it. I set about reorganizing, rewriting, documenting, abstracting - all those soft changes in pursuit of clarity and obviousness. They aren't objective, but they do pay off: when I handed the system off to the next guy (and three more after him!), he was off and building on it in a day. That was how I knew I had succeeded! When doing that sort of thing, you do always wonder if what you're writing is clearer for everybody or just you. But surely even the most hardheaded bean counter can see the value of training developers in a day rather than a year. That's good. :)

Goodness is contextual and subjective. I can agree that your goals are generally right, and I can point to circumstances where they're overemphasized or even outright wrong. Sometimes, when the sky is falling, a nasty little bash script that meets none of the usual criteria for "quality" is the best possible thing.

There are people who use subjectivity as a haven for vanity, and build mountains of pointless code in pursuit of some idea of goodness that serves no practical purpose or is even harmful. It is important that we retain our on ability to criticize on subjective grounds, precisely to counter that sort of activity - because you will find it in the land of the objective advocates as well, building mountains of metrics that don't serve any practical purpose either. To recognize a bad abstraction and a bad metric is the same skill, and requires the same confidence in your own good judgement.

Objectivity is no refuge from the necessity of good taste.