It's a qualitative word for a qualitative assessment.
For example, it is quite possible that code that is nested 30 levels deep is provably correct. Since we are humans, is that likely? No, it is not. Or at least, it is certainly less likely than 3-level-deep code. So you look at some code and without doing any deep analysis you can make some "probably valid" assumptions which come from your experience.
If you're so bent on accurate engineering, answer me this: Why are technology choices often "fashion-driven", without any significant empirical data to support their choice over other alternatives? (My latest pet peeve in this space is widespread use of Docker.) And where data DOES exist (such as to support the statement "Functional languages produce far fewer bugs per LOC written"), why don't more programmers/engineers heed that?
For example, it is quite possible that code that is nested 30 levels deep is provably correct. Since we are humans, is that likely? No, it is not. Or at least, it is certainly less likely than 3-level-deep code. So you look at some code and without doing any deep analysis you can make some "probably valid" assumptions which come from your experience.
If you're so bent on accurate engineering, answer me this: Why are technology choices often "fashion-driven", without any significant empirical data to support their choice over other alternatives? (My latest pet peeve in this space is widespread use of Docker.) And where data DOES exist (such as to support the statement "Functional languages produce far fewer bugs per LOC written"), why don't more programmers/engineers heed that?