With the growing popularity of RNG Breeding, any breeder knows what spread they are breeding for. Simultaneously, you can see the adjacent and nearby frames and what spreads you will get if you hit the wrong spread. I devised a tactic to help figure out "when to stop" before you start checking your IVs with a tool like Metalkid's IV Calculator, saving you a bunch of time. This will allow you to eliminate any other possible frames by merely glancing at its stat. This is mainly for use with Emerald, since the eggs hatch at Level 5. It can be redone to fit Level 1 Pokés, but for now we'll go with fivers. Example:
You are looking to hatch a Kecleon with an Adamant nature. We'll assume that you are ready to pick up your egg and the PID is already set. In RNG Reporter, you have your target frame and some adjacent frames. For the sake of simplicity, we'll only worry about Attack and Special Attack (these frames are made up, this is an example!)
x/29/x /14/x/x
x/21/x/29/x/x
x/31/x/12/x/x <--- Target
x/26/x/25/x/x
x/4 /x/31/x/x
It's tempting to just calculate Kecleon's Attack stat at Level 5 should its IV be 31. This yields an Attack stat of 16. However, three nearby spreads also satisfy this requirement, so if we hatch a Kecleon with an Attack of 16, it only eliminates the last frame listed. It would be better, then, to see what frames we can eliminate by looking at a different stat, namely its Special Attack. Kecleon's base Special Attack is 60. Moving onto the stat for a -Nature SpA (Adamant), yields
SpA = floor{ [(2*60 + IV + 0)*5/100 + 5]*9/10 }
= floor{ [(120 + IV)/20 + 5]*9/10 }
= floor{ 1080/200 + 45/10 + 9IV/200 }
= floor{ (1080 + 900) / 200 + 9IV/200 }
= floor{ (1980/200 + IV/200) }
= floor{ 9 + (180 + 9IV)/200 }
we can now isolate 9 from the floor function, yielding
SpA = 9 + floor{ (180 + 9*IV) / 200 }
Now, let's say that we hatch our egg and quickly glance at its Special Attack stat. We see that it's 11. This implies:
floor{ (180 + 9*IV)/200 } = 2
180 + 9*IV >= 400
9*IV >= 220
IV >= 25
Three of those spreads have a SpA IV >= 25, none of which include our target frame, so we turn the game off and start over.
Now, let's say we take a quick glance and see that its Special Attack is 9. This now implies that:
180 + 9*IV < 200
9*IV < 20
IV <= 2
None of those spreads have a SpA IV of 2 or less, meaning we hit some frame way out of that range, so we turn off the game and start over.
Obviously, we'll wait until we get an egg with a Special Attack stat of 10. If we do, that implies that:
200 <= 180 + 9*IV < 400
20 <= 9*IV < 220
3 <= IV <= 24
Two of the spreads in that range satisfy that requirement, one of which, of course, is our desired frame. From there, we rare-candy up as usual and try to narrow it down to just our spread.
