Google have released a new version of the Analytics tracking code referred to as “asynchronous”. This was officially released as a "beta" on Tuesday and is now being tested more widely. This is effectively a faster loading piece of code that is designed to sit at the top of a web page rather than the bottom. This means that for websites that have slower loading pages, the new tag will be triggered more often and should reduce the number of occasions when data is not collected accurately.
For typical websites, the accuracy with the previous tag is generally adequate – although I am sure most sites will move to this new script in time – this is really designed for sites that have page load issues (e.g. huge amounts of scripts or rich media content on the page).
We are testing the tag currently and will be recommending it to Clients as and when we identify a significant benefit.
Read more on the Google Analytics blog.