At Union Metrics, we provide a measure of potential exposure or impressions on Twitter. This shows you how many total timelines your tweets were delivered to, and it counts the maximum total impressions possible for your tweets.
Twitter’s analytics calculate actual impressions for each of your account’s tweets. It shows how many times people actually saw that tweet, while Union Metrics calculates total possible impressions for those tweets. Use actual impressions and potential impressions together to fully understand your impact on Twitter. The number of actual impressions received will vary, but your actual impressions will likely be between 1% and 20% of your potential impressions.
Knowing how your actual impressions compare to your potential impressions shows you exactly how well your tweets are performing, how large your audience is, and how large your audience could be. You can also use other Union Metrics stats on engagement (like retweets and replies, average retweet rate) and contributors (such as contributors who have engaged and generated the highest exposure) to understand not just how far your content is reaching, but how and with whom.If you'd like to learn more about how to use these metrics, read this and this.