A marketing report is a collection of data from different marketing sources that helps make sense of the results of your efforts. Marketing reports show the data, good or bad, to help you draw important conclusions that can inform your marketing strategy.
Marketing reports include information like:
Your marketing KPIs or goals
Market research on current and potential customers
Ad and email click-through-rate, open rates, etc.
Numbers on how your performance compares to other brands and competitors
Social media engagement rates, follower growth, impressions
These numbers help justify your efforts and highlight the success of your work. All in all, a report gives you the information you need to make more strategic decisions around your strategy.