if (is_page(**PAGE ID**)) not working

Question:

I'm following this tutorial on adding Google Content Experiments code to header.php.

I added the following code to header.php:

<?php if (is_page('346') ):?>
    <!-- Google Analytics Content Experiment code -->
        ...
    <!-- End of Google Analytics Content Experiment code -->
<?php endif; ?>

This didn't produce the content experiment code on the front end. I tried:

<?php if (is_page(346) ):?>
    <!-- Google Analytics Content Experiment code -->
        ...
    <!-- End of Google Analytics Content Experiment code -->
<?php endif; ?>

This didn't work either.

Can you see why this code is not working? Thanks.

Answer:

A simpler solution will be to pass the title or the slug as argument in is_page(). You won't have issues if you duplicate that page on another server.

<?php
if (is_page( 'Page Title' ) ):
  # Do your stuff
endif;
?>