The campaign analytics tab shows the following information

• Chart of new constituents recruited by month - this is for the year given on the campaign profile - if no year is specified the current year is used
• Chart of donation amount per month 
• ROI - Return on Investment - this is worked out from the campaigns actual expenses and the total amount given
• Response Rate - this percentage is calculated using the audience size on the campaign profile and the number of gifts received
• Actual Expenses & Budgeted Expenses are worked out from the expenses you have entered - for more information see this article 
• Statistics relating to gifts - e.g. smallest gift, largest gift etc - are worked out from the transactions linked to the campaign
• If any opportunities are linked to the campaign then a summary is shown of the opportunities 
• If a Mailchimp campaign has been linked, this will show in the analysis section at the foot of the page.