PHP - How To Improve This Inconvenient Function : I'm making a function to return whenether or not the given user ID is a staff member of the site. This is what I have and it works, however I feel like it can be greatly improved and I'm taking a wrong turn of doing what I want to achieve:

	public function isUserStaff($uid) {
		$stmt = $this->conn->prepare("SELECT user_role FROM users WHERE user_id=:user_id");
		$stmt->execute(array(':user_id'=>$uid));
		$userRow = $stmt->fetch(PDO::FETCH_ASSOC);
		
		$role = $userRow['user_role'];

		switch($role) {
			case 3:
				return true;
				break;
			case 4:
				return true;
				break;
			case 5:
				return true;
				break;
			case 6:
				return true;
				break;
			case 7:
				return true;
				break;
			default:
				return false;
				break;
		}
	}

I hope someone can help me out and describe how I can make my code better.