Are We More Likely to be Surrounded by Older or Younger Alien Civilizations?

One of my favorite astronomy channels on YouTube is Cool Worlds Lab, based out of the Department of Astronomy, Columbia University, and hosted by Dr. David Kipping. Professor Kipping does a (pardon me) stellar job of explaining complex astronomical ideas in extremely clear and digestible ways.

Case in point. In this video, he and his colleagues ask the question: Are we more likely to be surrounded by older or younger alien civilizations? They use statistical analysis based on a single data source (Earth) in a very enlightening way, and Dr. Kipping explains why it is still a fruitful analysis, even with only a single data set to work with.

Tl;Dr: We are significantly more likely to be surrounded by older alien civilizations. Watch the video to understand why.

Professor Kipping pins a fascinating response in the video’s comments, based on a question many viewers had:

Very common question I’m seeing here, and indeed honestly a very common question students have in my classes about statistics, is what if one of the oldest civilizations applied this reasoning – wouldn’t they get a totally different and wrong answer? Yes they would, but that’s how statistics works! Not everyone is guaranteed to be right every time. The oldest civilizations in this scenario would be the rarest and thus although they would arrive at the wrong answer, the majority of the sample would arrive at the correct answer. Think of it like this – if you state there’s a 90% chance of an event occurring, you will predict the wrong answer 10% of the time. That’s not a failure of statistics, it’s intrinsic to how it works as everything has uncertainty. All we can do in statistics is make probabilistic statements e.g. this is the most likely outcome, or this happens 90% of the time. Challenging to explain this in a single comment, it takes students a long time to grasp this concept usually but I hope that helps!