I didn't get that. OP says its for "evaluation," which is why I quoted that line of the OP.
As Psikey points out, he's "evaluating" the stories on their science content, not their use of language, imagery and general writing skill, which are not unimportant but of less interest to him. Many past hard SF stories weren't dazzling on the writing front, but are valued for their science ideas and treatments. The New Wave in SF in the 1960's and 1970's, which concentrated mainly though not exclusively on sociological SF, post-apocalypse, dystopias and utopias, etc., with an eye to concentrating on writing and language skill and sociological themes such as politics, sexual issues, and culture more than scientific ones, is not a particularly interesting movement to Psikey. (Although he does like Bujold's Miles stories even though they are an inheritor of New Wave SF.) Essentially, Psikey feels that only hard SF and some other stories that use some hard science fit the rubric of SF, per Sturgeon's definition. (Never mind that many of Sturgeon's SF stories didn't fit the definition.) Other stories that get called science fiction -- space opera, time travel, etc. he regards as not really having to do with real science and not real science fiction. He may read them, but he finds the lack of interest in hard SF stories in more recent times puzzling. He finds some aspects of quantum physics acceptable as hard science and other aspects as not really science. (How do I know all this? We've had this conversation many times.)
This is not at all a strange viewpoint in SF fandom. Many fans of SF feel that SF should be a term reserved mainly for hard SF. Other stories may be good, even seminal, but since they don't deal chiefly with a biological, chemistry, physics or engineering problem, they view them as fantasy or some other form of speculative fiction. (Although I haven't run into as many with Psikey's view on quantum matters.) Many others have a wider definition of SF, which all basically boil down to there being a scientific basis for the story and its universe, rather than a fantastical one, which can then range from background/world to central hard science issue. And the sub-categories that we use for the category SF market are based mainly on the science in the stories, what kind and how it is used -- hard SF, sociological SF, cyberpunk, space opera, military SF, etc., reflecting that we tend to view SF stories through the science lens for general content when describing them.
So Psikey's scale basically is just a three prong breakdown of the usual SF market. Category 1 is alternate history, time travel, comic SF, most space opera, some sociological SF, post-apocalyptic SF, some alien contact or invasion stories, etc. -- things that occur with the background of science and the use of some science but are not about the science and explaining the science. Category 2 includes most sociological SF, some space opera, some alien contact, military SF with its weapons, cyberpunk, planetary SF, etc. -- things in which science is involved and may have some explanation about it but hard sciences are not necessarily central and the main focus. And Category 3 is the hard SF stories, along with a few that have hard SF with solid explanations as sub-plots -- stories that mainly focus on hard science problems or issues or have them be integral to the story. Basically, it's a how hard is your science fiction scale, with 1 being not hard, 2 being moderately hard, 3 being very hard (and no, you cannot make jokes here.) As such, it's a quick notation about content.
But we already, as mentioned, have this scale somewhat in place in sub-categories. If a work is called space opera, then we know it's probably Category #1. A hard SF story is category #3. Cyberpunk is usually put in #2, unless it has very detailed explanations that computer and engineering folk do not consider hokum. Sociological SF is usually #2, etc. and will be focused on social science issues placed in a scientifically altered, usually future, reality. So we already use Psikey's scale pretty regularly in SF. Terming Category #1 books as not SF, however, no matter how much some SF fans want it, is not going to happen. They are part of the SF universe, using science -- hard science -- to create a story universe in which things could not happen without that hard science. But they are not focused on that hard science itself, but instead on the ramifications of the universe created by the hard science -- the culture, life, conflicts, moral questions, etc. of that universe, rather than exploring all the details of the science underneath, and often using the faintest of scientific speculations to give their story a science basis.
So John Scalzi's Old Man's War, military SF, would be in Psikey's Category #2. It has hard science very much creating the universe and the circumstances of it for the main characters, biological and technical processes are explained or partly explained, but the detail only goes so far. And the story is focused on issues related to that hard science underpinning but not about the science -- issues about aging, moral issues of war, politics, etc. And something like Peter Watts' Blindsight, hard SF, would be Category #3. Watts is very interested in action, politics, cultural issues, etc., and the story is about contact with aliens, but he offers detailed explorations of neurology, biology, physics and tech and the story centers on unraveling the hard science questions of the aliens' nature. Something like Flowers for Algernon or A Canticle for St. Leibowitz -- neither of them is without science, hard science as the underpinnings and critical factors of their universes. But in terms of detailed scientific content -- they don't really have it. And so both stories, seminal to SF, might be considered Category #1, or #2 at most. None of this has anything to do with writing quality. It's strictly about how much science material does the story have and how central it is.
