The difference between impact and reach

Hashtag’s reach and impact: a key metric on Twitter.

Reach and impact are two of the main metrics we should use to measure the success of a campaign or event on Twitter. Impact (impressions of the hashtag) is used to see how many time the hashtag could have been seen. Reach would be the audience of the hashtag, how many people could have seen it. The definition of both would be:

Impact: how many times the hashtag could have been seen by Twitter users.

Reach: how many people could have seen the hashtag.

Impact

To calculate impact we do a very simple calculus. Since what we want to measure is the number of times that the hashtag could have been seen we will go user by user multiplying the number of followers by the number of tweets. Then after that we will add all these user results.

Let’s see an example:

Example: We are at an event and the hashtag is #TweetBinderEvent2016, then we have 10 tweets sent by 2 users. These users are:

  1. User_Example_01: 10 followers and 3 tweets sent with the hashtag #TweetBinderEvent2016.
  2. User_Example_02: 50 followers and 7 tweet sent with the hashtag #TweetBinderEvent2016.

So we have 10 tweets with the hashtag #TweetBinderEvent2016 sent by 2 users. Let’s calculate now the impacts of each one of them:

  1. User_Example_01: 10 followers and 3 tweets. 10 x 3 = 30 impacts.
  2. User_Example_02: 50 followers and 7 tweets. 50 x 7 = 350 impacts.

We can say then that the hashtag #TweetBinderEvent2016 generated 380 impacts.

As you can see, the number of followers is very important when talking about impact, not only the number of tweets. And one last thing, not everyone is on Twitter all the time, so the number of impacts will be always “potential”.

Reach

To calculate reach we will do another simple calculus, we will add all the followers of each user who participated in the hashtag, the number of tweets in this case is not relevant. We will continue with the previous Example:

Example: In the same event  #TweetBinderEvent2016 we still have 10 tweets sent by 2 users:

  1. User_Example_01: 10 followers.
  2. User_Example_02: 50 followers.

In this case we will just add everyone’s followers and we will get the global reach: 10 + 50 = 60 users reached. So, if we combine both metrics impacts and reach, we could say that the hashtag #TweetBinderEvent2016 generated 380 impacts on 60 users.

At this point we must note that “reach” is also “potential” because not everyone will be on Twitter to read the tweets and also there might be followers in common in these 2 users that tweeted.

Some people say that the “Reach” of the hashtag stays for the number of “Visitors” of your website and that “Impacts” does it for “Visits”. A visitor can enter your site more than once as well as a Twitter user can be impacted more than once.