Best place to insert the Google Analytics code
As google says:
Paste it into your web page, just before the closing
</head>tag.One of the main advantages of the asynchronous snippet is that you can position it at the top of the HTML document. This increases the likelihood that the tracking beacon will be sent before the user leaves the page. It is customary to place JavaScript code in the
<head>section, and we recommend placing the snippet at the bottom of the<head>section for best performance
Google used to recommend putting it just before the </body> tag, because the original method they provided for loading ga.js was blocking. The newer async syntax, though, can safely be put in the head with minimal blockage, so the current recommendation is just before the </head> tag.
<head> will add a little latency; in the footer will reduce the number of pageviews recorded at some small margin. It's a tradeoff. ga.js is heavily cached and present on a large percentage of sites across the web, so its often served from the cache, reducing latency to almost nil.
As a matter of personal preference, I like to include it in the <head>, but its really a matter of preference.