thief actions

can someone explain this section of code to me? I want to change it to make it easier to have a success instead of a fail.

// Process their chance of failure.
	$failure = 50;
	if ($action['maxrep'] >= $thefted['reputation'])
	{
		$addfailure = (($thefted['reputation'] / $action['maxrep']) * 50);
		$failure = ($failure + $addfailure);
	}
	else
	{
		$fail = 1;
	}

	$random = rand(0, 100);
	if ($random <= $failure)
	{
		$fail = 1;
	}
	
	if ($fail == 1)
	{
		$failtext = "Failed";
	}
	else
	{
		$failtext = "Success!";
	}
	
	if ($fail == 1) {