I've noticed when checking over the total column calculations that the figures per day don't add up to the total figure. I was wondering is this a mistake or is there some margin of error that's accounted for in these calculations? Any help with this issue would be greatly appreciated
Its the definition of "Unique Visitors" due to which figures per day don't add up to the total figure. A unique visitor is a metric referred to an individual who has visited a site for the first time within a "certain time period". So its unique for the time period that is selected in Adobe Analytics reporting framework. Hence a visitor visiting daily for the first time would be counted unique daily, but for a broader time period selected e.g., for a week it will be counted unique for that selected week when he visited for the first time. Say if the unique visitor could have visited a site 10 times in a week, but if the time period specifies unique visitors for that week, a single unique visitor will only be counted once for that week. Because of this when you add per day will never add up to the total shown by Adobe Analytics. As a best practice its recommended that you should never add per day/ per week/ per month/ per year Unique Visitors to get the total, always use the total figure shown by Adobe Analytics for a selected time period.