I'm actually finding this comment chain useful, because I see it as showing that we need better language to describe the stages of design. Or maybe that nomencl

I'm actually finding this comment chain useful, because I see it as showing that we need better language to describe the stages of design. Or maybe that nomenclature does already exist but people aren't using it? In R&D we will often describe the https://en.wikipedia.org/wiki/Technology_readiness_level https://en.wikipedia.org/wiki/Technology_readiness_level of a new technology, and this is much more useful that just saying "it's in development". But I'm not aware of a similar shorthand for the design phase. There is this muddy space between concept and fully specified design which would be awesome to be able to talk about in more concrete terms. For example, let's look at the concept/design of a helicopter: DL1 (idea phase): a flying machine that can go straight up and hover DL2 (concept with basic working principle): a vehicle with a rotor which acts like wings moving in a circle to move air down and by reaction push the vehicle up DL3 (concept with important details attached): as DL2 but with a tail rotor to allow for axial control and differential tilting of the airfoils to allow forward thrust DL4 (concept with specifications that drive requirements for other specs): as DL3 with rotor lengths of 3.3 m and a NACA 0018 cross section made of 6061-T6 aluminum DL5 (concept with full specs): as DL4 but also etc. Is anyone aware of better nomenclature like this for the concept/design phase? It would help for more important things than this discussion alone. Like when discussing which is more important, idea or execution: so which level idea are we talking about? Also, the root cause of a lot of software problems is in the spec. It would be nice to be able to go back and say, "this spec is only spec level 3, can I please have a spec level 5"? This discussion is happening because "they designed it over a weekend" is really vague. It would be nice to have a quick way to make it not-vague.