"Retweet" means multiple things, so for clarity we'll separate the meanings into two buckets:
- Interactions on your original tweet. You post a tweet, someone else retweets it, your original tweet now has one retweet.
- Retweets that you create of original tweets by other accounts. You retweet someone else's tweet, and the retweet now shows in your timeline.
TL;DR: #1 is in CrowdTangle, #2 is not.
For tweets, to calculate interactions, we measure likes and retweets on tweets. So retweets are counted there. (#1)
When we pull tweets from an account, we only pull original tweets; we don't pull tweets by other accounts that this account has retweeted. (#2)
So for example, if @crowdtangle tweets about a new feature that we're launching and @facebook retweets it, that tweet's retweet count goes up by one (#1). If you were to check @facebook and try to see that tweet, it would appear on the timeline, but would not get brought into CrowdTangle (#2).
The reason for #2 is that retweets are not really treated as separate tweets via Twitter's API, and the interactions on the original apply to all retweets. So if @crowdtangle were to retweet the most popular tweet of all time, it would appear that our tweet has millions of likes after just a couple seconds, destroying streams and leaderboards. As a result, we only bring original posts into CrowdTangle.