To claim your findings matter beyond your lab, another researcher somewhere else needs to be able to reproduce them. Plan for replication from the start, especially when you're claiming strong relationships between variables.
Once we've set up a study that is internally valid, how do I make sure that external validity is there? Protecting for external validity, you want to think about things like can this study be replicated? And by that I mean can somebody else at another location with another sample come up with and do the same study? Or can they take my research and try it in a different way with a different sample or a different methodology or something? So externally, will someone else be able to replicate what I'm doing? This is really important. If you start saying, well, A is associated to B or X has a strong relationship to Y, you want to make sure you've designed your study so that it can be done again. Drop the word help in the comments and I'll send you a link to my free dissertation help community.
