Do "no effect" natures really have no effect?

On both Bulbapedia and Pokemon Database, the “no effect” natures still have stats corresponding to them, only that the increased and decreased stats are the same. Does that mean the games really increase and decrease the same stat? For example, if a Pokemon had a serious nature, its speed would be multiplied by 11/10 and then by 9/10, resulting in its speed being multiplied by 99/100 and being slightly slower than if it had a nature that really didn’t affect speed. Is this true? Has anyone tested it or read the code?

Pleaselog inorregisterto add a comment.

(I’m not 100% sure whether this should be an answer or a comment, since it relies so heavily off of information in the answer by~Rex. But, I decided to make it an answer because I feel that I provide a decent amount of new information as well as a definitive answer)

Okay, so I don’t have SM (haven’t kept up with the main games in favor of Showdown), but I was just so intrigued by this question that I tested this out in White, the most current game I have.

Cinccino, Lv 100Serious Nature31 Spe IVs0 Spe EVsResults on Showdown:266 SpeResults in White:266 Spe

So we can finally conclude that neutral natures truly are neutral. Even though this was tested using a Gen 5 game, I strongly doubt that Game Freak would have changed this in Generation 6 or 7. So, I think we can all agree that these are adequate results, unless somebody comes and proves that natures really did change since Gen 5.

Okay so, stats are calculated thus:

Which means, to create a simple model using alevel 100 Pokemon with a base speed (for example) stat of exactly 100, with zero EVs and zero IVs,

we would have its speed as [{(2x100+0+0)x 100}/100] + 5, and all of that into nature multiplier.

Now, in stat calculation as seen here

The stat is rounded down if the result is a decimal. The stat is also rounded down before the Nature multiplier, if any, is applied.

That is part one, till where facts are available.

Part Two:Conjecture

This part is based on the assumption thatwhat Bulbapedia has stated is true:

Every Nature represents one of the 25 unique possible combinations of stat increase and decrease; thus, there arefive Natures that have no effect on the Pokémon’s stat growthas they technically increase and decrease the same stat (Bashful, Docile, Hardy, Quirky, and Serious).

and

The stat is rounded down if the result is a decimal. The stat is also rounded down before the Nature multiplier,if any, is applied.

If we consider these two phrases, then a simpler alternative comes into play:

Taking that idea, then it is simple to see how neutral naturesdo not affect the stat at all, because thegame uses multiplier, which is a single value. And obviously, as we all know, multiplying any value with one gives the exact same number. Now, I’m no coding expert, but if you can assign a multiplier to each nature as 1.1 or 0.9, then just as simply the multiplier can simply be 1.0, instead of 99/100, which is 0.99. This also makes sense if there is a strict line of coding that allows just 3 characters to define the multiplier, withthe middle character set as a decimal value, leaving the first and last to have 0,1 or 1,9 respectively. If my idea is correct, then the last digit can also be a 0, meaning a 1.0 multiplier is perfectly possible.

Again,ifthere is a character limit of 3 (decimal inclusive) then 0.99 can not be a valid combination. Again, this is confirmed only by looking at that exact line of code, and that will reveal if part 1 is correct, or if my hypothesis holds water. Either way, the loss is by one single point at the most.

Of course, there is, to be honest, no way toproveit, as fizz’s edit wants, but I thought this was an idea that I could put as an answer. One particular strength behind this is that it views the nature multiplier as just that, a multiplying factor that is not directly added or subtracted from a stat. I tried focusing on how the stat is affected by the multiplier, so I thought this could shed some light. Feel free to leave comments below if you agree or disagree, and we’ll make try to make changes as it develops.