Your team influences what pokemon you find and wether it will be shiny or not!
Say I was taking a strole through mt.moon in FR.
My team consisted of Bulbasuar, Ratata, and JigglyPuff.
The most common pokemon to find are;
If I put Jigglypuff in 1st position, Clafairy encounter rate would shoot up by 20%!
Is it was a Shiny Jigglypuff then the chances of finding a shiny is doubled!
Reserch isn't that far in, so if your willing to help, give us a ring on 000 000 000...just pm me.
Now Ima gonna go and do more research!