NERD ALERT: This article uses math symbols and includes an SAT math problem. Thankfully, no right-brained thinkers were harmed in the writing of this article.

You’ve surely heard the term half-life. Written as t1/2, it’s often used in the context of radioactive decay. But did you know t1/2 also applies to social media? Understanding your posts’ t1/2 will help you make smart decisions about your social media marketing.

So, what is t1/2 in social media? It is how long a post takes to reach 50% of its lifetime engagement. (By the way, we’re talking about engagement in organic posts, not in paid advertising.) Engagement is any action people take on your posts, such as likes, comments, shares, and clicks.

Got it? Great! Now go ahead and solve this SAT problem:

Your company participates in a 5k and posts a Facebook album to celebrate the event. Facebook fans engage with your album for 12 days with 150 total likes, comments, shares, and clicks. Of those engagements, you get 45 in the first 3 days, 30 more in the next 2 days, 20 more in the 3 days after that, and all other engagements in the remaining 4 days.

What is the t1/2 of your album?

  1. 5 days
  2. 6 days
  3. Choose this, because the answer should always C.
  4. 8 days

Hopefully you arrived at the correct answer, (A). This is because you received 75 engagements (45 + 30) in the first 5 days, and 75 is 50% of your total 150 engagements.

Now, let’s be real. Your company’s social media posts will rarely enjoy a t1/2 of 5 days. Here’s the average t1/2 on the most popular sites:

Instagram – 19 hours
Facebook – 30 minutes
Twitter – 18 minutes
LinkedIn – No available data

Does this mean you should post every 19 hours on Instagram and every 30 minutes on Facebook? Absolutely not! Posting just a few times a week is a healthy frequency and is much more realistic for small businesses.

What it does mean is that you should follow best practices to increase engagement; this will ultimately increase your t1/2. Your action items include:

  1. Be intentional with your posts. Don’t just post a bunch of random stuff so you can be “on” social media. Instead, share content that provides value, whether it’s entertaining or educational. Aim for quality—not quantity!
  2. Post video—especially live video—whenever possible. Video typically gets the best engagement. This can be anything from behind-the-scenes footage to topic-focused tutorials.
  3. Post updates that showcase people. Employee and customer spotlights are always popular!

In addition, understand that you can’t rely solely on organic posts to make a dent in social media. You need to also invest in paid advertising. This allows you to reach a much larger, targeted audience that is more likely to engage with your posts. Set aside a monthly budget—$50 at the bare minimum—to reach more of the right people and achieve much better results.

Finally, have some fun with t1/2 to calculate other aspects of your life! What is the t1/2 of your morning cup of coffee? How about the t1/2 of “fake news”? The list goes on.

Happy posting, and reach out to me at whenever I can help you!

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