I think one thing you can add is the 'quality' of chances/shots a player like Sterling has at City compared to your other players.
It's not quantifiable (or is it with those XgFtabclolbbq!11 +/- stats?) but that's the point a few are trying to make when they're trying to judge his effectiveness.
Yeah. The following isn't all necessarily aimed at you (more the thread in general) but you've accurately represented the basic thrust of my perspective and here I'm going to expand on it.
Measuring "clinicalness" in a quantitative way remains very difficult, even more so if you want to be objective about it. In fact, I'd argue that it's an intractable problem, almost by definition. But some ways are clearly better than others.
If you require determinism from your football statistics - I don't think there's a convincing justification for that but if it's just one's subjective preference, fair enough - then goals/shots ratio is the best metric you can get using easily accessible data. But for any sample size upwards of about half a season of matches, G/xG kicks the shit out of G/S using any modern xG model (which are getting better all the time as feature selection is refined). As I've said before in this thread, G/xG is the gold standard measure of clinical finishing for any sample size large enough to smash the margin of error inherent in derived/stochastic models (half a season, as above, is a conservative estimate of the required data; you can probably make accurate predictions from far fewer games).
Personally, I derive all my conclusions with respect to "clinicalness" from G/xG ratios (since those are, as I say, the best numerical estimates we have available to us). If G/xG ratios from the last six seasons are taken a step further (beyond what's available to most people) and the question becomes "whose record is least likely to belong to an average player?", the only finisher in the world more clinical than Harry Kane is Messi (hence I always use Kane as my default epitome of clinical striking in talking about, especially, the PL). (I can't explain p-values and everything else involved in the validity of the question/conclusion because I'd have to somehow give a university stats lecture - with lots of prerequisites - in a forum post! The important thing is that G/xG itself is not hard to understand: read as "the ratio between the number of goals a player scored and the number of goals they were expected to score" [this reading has the clear benefit of illustrating exactly why G/xG is the gold standard in the first place].)
Regardless of whatever post-hoc manipulation you perform on G/xG, Kane still comes out as one of the 3 or 4 most clinical finishers on the planet. Although not close to surpassing Kane overall, players like Vardy, Salah etc. are also elite finishers who typically outperform their xGs significantly (hence my constant use of them as examples of other excellent finishers).
G/xG produces results that surprise a lot of people, even when they shouldn't be surprising. For example, I don't really think it should be surprising that Aguero isn't actually
that clinical (none of City's forwards are). If Aguero, playing for a team that has oscillated between dominant and terrifyingly dominant while breaking team goal records, still only has the same overall GPG as Kane, playing for a good side that has never been close to dominant, why wouldn't Kane come out to be much more clinical than Aguero? That's common sense to me.
Other titans of the game like Lewa and CR7 are also not particularly clinical. Last season, Lewa had one of the worst G/xGs I've ever seen from a top-tier striker. Those guys have never really had to be clinical, and they can still score bags while not being clinical. That's the difference the quality of your team makes: fecking enormous, and G/xG is the only stat that very obviously discriminates between a great finisher and a finisher with a high volume of easy chances. The only titan of the game who lives up to his reputation in these objective terms is Messi (and Kane, if you count him -- I'd argue that if one's counting Lewa, Kane should be there too).
In most years, Sterling glances his xG (and thus has a negative, i.e. <1, G/xG ratio overall). He never significantly outperforms it. The best fitting interpretation of his xG data is that given the quality of chances he gets, he scores about as many goals as you would expect a professional footballer to score. (Nonetheless, it's not a huge deal: his G/xG is 0.97 but Aguero's is only something like 1.04 so the difference is hardly chasmic -- for reference, Kane's is approximately 1.20.)
As you say, this is what people like me are suggesting about Sterling: that his raw finishing ability when he has the ball in a shooting position is just mediocre. I'm not trying to suggest anything else on top of that, however, and would distance myself from his more general critics. I think he's a great player overall -- albeit one with important flaws, including his finishing, which neither looks good statistically nor passes the eye test (IMO). I think the eye test (which, even despite my advocacy for stats and objectivity, I still regard as the single most important factor) corroborates the picture created by G/xG: you never see Sterling score - or even look like scoring - the kind of screamers that would match up well against Kane's best goals.
I find myself being misrepresented on here too often. I've never said that Sterling wasn't/isn't a great player. I merely contribute most to the discussion of his finishing ability, which may seem like a focus on his flaws and therefore seem like criticism. In reality, finishing is just the part of football that interests me the most, and the part on which I have related expertise to share that few others will offer in comparable depth.
incredible how he always has these sitters in him