‘Redirect with live query parameters included’ is an option provided in split URL experiments. Once you select this option, all the query parameters (of your original URL) such as source, medium etc. will automatically be copied onto your variation URL.
For eg. Let’s say you are running a split URL experiment with the following URLs
Original URL: www.xyz.com/
Variation URL: www.xyz.com/b.html
‘www.xyz.com/?utm_medium=email’ denotes that the visitor has landed through email. However, when the experiment redirects the visitor to the Variation URL, the query parameters are not generally included.
Hence, selecting the option ‘Redirect with live query parameters included’ will ensure such URL parameters are included for the Variation URL as well and thus prevent any loss in data.