What determines Catchability of Pokémon?

//ads -- adsterra.com -- native banner
?>
I've noticed that after beating a stage, the initial Catchability percentage will be very low, despite being what I would consider a good game. It then adds on additional percentage for moves that were unused.
What I don't understand is how the initial percent is calculated. I can do really well on one stage and get a low percentage, but do pretty badly on another and get a high percentage. How is the Catachability determined?
Pictures about "What determines Catchability of Pokémon?"



राजनाथ की हुंकार 'PoK हमारा था, है और रहेगा' | Rajnath Singh on POK | Pakis
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Katya Wolf, Ann H, Andrea Piacquadio, Andrea Piacquadio