[garethrowlands]

I think engineering increasingly sees goals that aren't very specific or necessarily accurate, that change over time and where meeting them partially provides value. Thinking about engineering in terms of trading time, cost and performance or quality is one perspective but these things are often very hard to trade and focusing on providing value is usually more reliable.

[KineticLensman]

> these things are often very hard to trade and focusing on providing value is usually more reliable

Good point and I completely agree. I just felt that not mentioning any of these things in an article on 'principles of design' understates the complexity of a real and principled design process.