It’s sometimes hard to resist the temptation and good feelings that come from when you discover something that works tremendously well for a landing page. It’s easy to think it could be applied to every website you ever work on.
But the truth is, the Internet and by extension the world is a very complex place. So mass generalizing the latest popular search engine optimization technique is a bad idea. You simply cannot derive universal truths from a single landing page’s test results.
Any “learnings” from a single landing page are likely to be uncertain at best.
Why? It’s because of what science dubs as “false causality”, meaning “correlation does not imply causation.”
This phrase is referring to a common error people make, no matter if they’re thinking about a science experiment or a webpage. That is, they assume that since two effects are related or occur together, one causes the other. However, this assumption fails to recognize the fact there could be a third variable, or confounding variable, that causes the other two.
In landing page optimization, it’s dangerous to rationalize results after the test. Rather than focusing on elements of design that had nothing to do with improving performance, try to come up with diverse and interesting ideas for each landing page test you do. Be forward thinking and do not simply accept the most apparent analytic answer.
Read in more detail this concept along with some real world examples from this Search Engine Watch article from Tim Ash.