How do you calculate Landscape averages?
For any single channel (Twitter, FB, etc) the Landscape Average is the mean (vs. median) of the values in a landscape. This is calculated by taking all values, summing them and dividing by the number of values. If a company is not present in a channel (either because it does not have a presence or because it is explicitly filtered out with a tag) then that company is not counted as a value used in a denominator.
Here’s an example: say there are four companies in a landscape, and three have a twitter presences. If the values for those three for twitter followers is 1000, 2000 & 5000, the Landscape Average would be (1000+2000+5000)/3 or 2,666.
The short answer for Average Landscape Engagement Rate is that it is calculated by summing up the Engagement Rates for each post that received >1 engagements and dividing by the number of posts that received >1 engagement.
For example if in the time period only 3 posts received engagement in the following fashion
Post A - 25 engagements on with a 1000 follower count = Engagement rate of 2.5 (2.5% of audience engaged)
Post B - 35 engagements on with 500 follower count = Engagement rate of 7 (7% of audience engaged)
Post C - 15 engagements on with a follower count of 1000 = Engagement rate of 1.5
Average Landscape Engagement Rate = (2.5 + 7.0 + 1.5) / 3 posts = 3.66