Ordering posts by Custom Field

I have set up a post custom field, called “schools” which contains school names.

I am using WP Custom Search widget to search on the “Schools” field.

In order to sequence the output I have amended the index.php with the following code prior to the loop to get the data displayed in alphabetical ascending (A-Z)

query_posts($query_string . ‘&meta_key=School&orderby=meta_value’);

It is giving me reverse alphabetical?