How do you force the wordpress dashboard to be 1 coulmn by default?

I found a promising looking answer to this question in the following post:
http://wordpress.org/support/topic/customizing-admin-area-using-functionsphp-2-questions

It recommends using this code in the functions.php file:

function so_screen_layout_columns( $columns ) {
    $columns['dashboard'] = 1;
    return $columns;
}
add_filter( 'screen_layout_columns', 'so_screen_layout_columns' );

function so_screen_layout_dashboard() {
    return 1;
}
add_filter( 'get_user_option_screen_layout_dashboard', 'so_screen_layout_dashboard' );

Hope that helps!