Including a hashtag in a social media message can increase its reach. The question is, what is the ideal number of tags to include?
To answer this question, I examine 60,919 original tweets sent in 2014 by 99 for-profit and nonprofit member organizations of a large US health advocacy coalition.
First, the following table shows the distribution of the number of hashtags included in the organizations’ tweets. As shown in the table, almost a third (n = 19,747) of tweets do not have a hashtag, almost 39% (n = 23,493) have one hashtag, 19% include two hashtags (n = 11,836), 7% include three (n = 4,381), and 2% (n = 1,161) include 4. Few tweets contain more than 4 tags, though one tweet included a total of 10 different hashtags.
Frequency of Hashtags in 60,919 Original Tweets
|# of Hashtags||Frequency|
Now let’s look at the effectiveness of messages with different numbers of hashtags. A good proxy for message effectiveness is retweetability, or how frequently audience members share the message with their followers. The following graph shows the average number of retweets received by tweets with different numbers of hashtags included.
What we see is that more hashtags are generally better, but there are diminishing returns. Excluding the 25 tweets with more than 6 hashtags, the effectiveness of hashtag use peaks at 2 hashtags, with more than 3 hashtags being only as effective or less effective than no hashtags.
The evidence isn’t conclusive — especially given the anomalous findings for the few tweets with 7-10 tags — but there is strong support here that, if you want your message to reach the biggest possible audience, limit your tweets to 1-2 hashtags.