Just going to reply to some of the people in this thread as I have been reading through it. Liking the discussion so far and it is interesting to see peoples views on things.
One thing I did want to bring us is the use of limited availability items. Do we take into account the fact that a person may want to save their Master Ball? I don't think we should, personally. Also on the subject of Master Balls, should the availability of this factor into a mon's tiering? It was brought up in the DP thread a while ago for mons like Mesprit.
Do we assume people will spend money on things like vitamins?
Generally agree with your post. Just wanted to reply to this one. I think using an item as important as a masterball is an interesting question. I presume in most instances for efficiency it would be wise to use it to capture your specific legendary unless you go into the fight willing to go for a slog fest/have the right set up. Again, this comes down to personal preference. If you want to use the Masterball to make that particular fight a lot easier, why not?
Coeur7 This is not a speed running discussion. We all agree on that part and
Merritt makes an excellent post about why this is not the case. Speed running will
always turn into "This 1 mon is best, these other 5 are decent, don't use anything else". That's not the sort of help we want to give people. We just want to guide the more casual player in their expectations of what they should expect out of a Pokemon.
What's the policy, if any, on Pokemon games featuring easy to perform glitches, such as item duplication in RBY or the Pokeball glitch in Colosseum? These could influence the allocation of theoretically limited resources, or ease the burden of obtaining something (the birds don't compete for the Master Ball, for example). These could be performed in game without significant detour most times, and since these seem to go by release (GSC is separate from HG/SS, for example), they seem like something to at least be clear about in the ranking rules, whether as a sweeping rule or on a thread-by-thread basis.
We did discuss the usage of X Items for Gen 1 ingame runs (because of they break the game so easily, especially in the case of X Accuracy + Horn Drill). I think we should accept that the item duplication glitch in Colo (which is super easy to perform) and other "easy" glitches (Cloning in GS/Missingno in RBY) might be used by the player, but I do not think we should endorse them for the Tier Lists. We should be looking at the game as it is, not as what it might be through glitches.
I suppose I should maybe contribute what direction I come from when making a post about efficiency on the threads, just to see if there's any faults with it. I've two fundamental ideas I always keep in mind: A) This is for casual runs. Not something where you have a definite goal in mind like beating the game in the best possible time or even aiming for in-game facilities; but just a normal play of the game you pick up from time to time for fun - and B) The lists do not denote what you should use; but rather accept that this is the Pokémon you are wanting to use, now here is a general guideline of how well it will perform.
What I see a lot of people falling into is that there is in some way some sort of specific goal to keep in mind when tiering these lists. This is why we've had a few people recently contributing formulas and speedrun tactics and the like, when really it's not so rigid -- the two fundamental ideas I put forward combine to basically say that there is not a specific goal or rigid set of rules or some ultimate answer we're trying to reach here. It simply deals with casual runs and attempts to inform people doing these casual runs how well they will perform. Not what they should and shouldn't do; not what goals they should be reaching; but as a general guideline of what they can expect from the choices they will make.
This basically hits the nail on the head for me. These tiering threads have always been about how a Pokemon
feels to use. We've had great discussion over what that means and also debates over whether waiting for an evolution of a mon is better than grabbing it at the earliest opportunity (Azurill vs Marill for example). I strongly believe these lists should be a generic list of how we expect any particular mon to perform across the most "average" of games. Yes, having more/less mons will improve/worsen your team overall, but dragging around Ledian will devalue your team much more than Gyarados for example.
Because this tier list is on the Smogon forums, the intent is to probably assume that the reader of the list has more Pokemon knowledge, but it's still good to clarify. Do we assume the reader assesses risk versus reward during battles? Do we assume that the reader can look at a Pokemon's learnset and "correctly" determine which moveset optimizes their chance of success during the game? Do we assume the reader can make an intelligent determination of which team members to add to a partial team in order to fill necessary roles and patch up weaknesses? In any event, I think the question of target audience knowledge is the first one to answer, followed by which criteria factors into a Pokemon's in-game viability.
I think we would mostly assume that the person reading a list like this would have a decent understanding of the game. They would know that Tackle -> Headbutt -> Return is a logical increase in power for a Normal type move (Similar stuff could be said for Water Gun -> Bubblebeam -> Scald/Surf). I would hope that the majority of Smogoners (and Pokemon players in general) would understand that certain moves are far better than others and they can make "intelligent determinations of team members". I do not think we need to go that far base level. Hell, if a
totally new player read these lists and went "OK these guys look cool" -> Picks a bunch of S/A/B mons and then an E/F mon, they would be easily able to understand why they are ranked in such a way.
As I have said above, whilst we look at "Efficiency" in these lists, personally I see these more of recommendations. If a mon is high tiered, you're going to have a much easier time with it in your party over those mons which we deem to be "worse". As others have said plenty of times, everything can work in game (and as I proved by using bottom of the barrel mons for an XY playthrough). I believe these tier lists help inform people of what to expect at a quick glance of any mon which is available in said game.