You can call the select method with FALSE as the last parameter, e.g.
$this->db->select("IF(predicts.predict_owner = votes.vote_user_id , IF(judges.judge_did_accept = 1 , True , False) , 'NotExists' ),'user_judgement'",false);
This will allow CI to add `
From user manual
$this- > db- > select() . FALSE, CodeIgniter . , select.
PS: , select "user_judgement", , , Cay CI, , Active Record