Bulbapedia:
If a Pokémon with Analytic executes its move after the Pokémon it originally targeted has already acted this turn, the power of its move is increased by 30%. Using a move and switching to another Pokémon count as having acted, while Mega Evolving, shifting, or the charging phase of Focus Punch do not.
So, you're referring to your target having already exited the battle through the use of, for example, Parting Shot or U-Turn, correct? The answer to that would be yes, Analytic does takes effect.