Discussion on: Write good PHP - Lookup-arrays

You've made the switch version look more verbose by changing return to echo, meaning it's no longer the same code as in the first example. If you were refactoring the first, you'd do:

$relative = $_GET['relative'];

switch ($relative) {
    case 'mother':
        return 'Harriet';
    case 'father':
        return 'Robert';
    case 'daughter':
        return 'Rachel';
    case 'grandmother':
        return 'Audrey';
}

That could do with a default, of course, but you know what I mean :)