It actually is just QPD but saying it like you would cupid makes it more memorable.
The short version is simple: Quality, Performance, Design.
You want something quality that performs well and then you look for which one looks better. This is a general way of how people select things and also how I’m approaching creating pretty much anything at all.
Let’s look at an example, because these terms are way too broad to make this easy understood at first glance.
A friend needs a frying pan. His old one is way too old so he goes to a store. There he has a selection of 20 different ones, ranging from high end to lowest crap. His need for quality is low, he needs a pan now and he knows no matter which one, after three years or so, the one he buys now is garbage anyways. He goes with one of the cheapest one, which will perform the task as equally as any other (or so close that there is virtually no difference). The design doesn’t even play a role, but I must say it’s a very ugly pan. Thankfully it’s a tool which is used temporary in the kitchen and spends the rest of it’s days in a cupboard. If he had a fancy kitchen where he hangs the pots up for display, he might chose something slightly less eye gauging.
Another friend want’s a new notebook. He has selected a Samsung or a Toshiba one, of the class of machines that are small and thin, but still fully capable notebooks. The quality is roughly equal as far as he can tell and the performance, well, it’s the same guts in essence anyways. So his decision is now down to design in the end. Which keyboard is more appealing, which casing, which screen.
So we almost always start out with a level of quality. That one is also determined by our budget more often than not, but quality is a huge key. Then in that range we look for performance, does it do the job well or better. And once those are satisfied, only then the true design is considered.
There are exceptions to this, like novelty items, or “cool looking thing” that you don’t really need or is impractical, but we select anyways for their design only.
In creating the quality is also paramount. A fine planed application or a quick hack. Performance, ignored (because of time constraints, not needed since it’s only a couple people using it) or highly optimized. And then in the end, a design (not application design, but the look and feel of it) to make it work smoothly or a like a huge kludge.
The principle applies rather broadly, not only to software as you can see in the samples, or purchases or projects. The sense also applies to relationships, to decisions in courses and so on. It boils down rather neatly, as long as you understand the fundamental contributors of quality, performance and design.
