How come is null?
Lets strip your code ...
You have this input in a form, you write something in that input:
<input name="school_type_other" size="30" maxlength="75" value="" />
After u submit your form, and u print_r() the $POST array it returns $POST['school_type_other'] = null?
Or the value from your input:
if ($_POST['hasReviewedApplicant']) echo $_POST['school_type_other']; else echo str_replace('"', '"', str_replace('', '', $result[0]->school_type_other));
is null?
And what is this code good for?
str_replace('', '', $result[0]->school_type_other)