What it is meant by that is what if someone studied a cemetery with little or no activity to a cemetery reported to have a lot of activity. Would there be different results? Would you respect different results and would that expectation have an effect on how you present the data after words? How do you get rid of variables that would effect the results?
It would be one thing to compare a cemetery to lets say an apartment. An apartment is not a cemetery. So in comparing two different areas that are in essence the same you would be able to begin a process where you can disprove or prove the existence of ghosts and spirits and how they behave. That means you should be able to some degree predict the behavior with certain accuracy if it was to exist.
I hope to put this together soon. I am really excited to see if I can capture anything let alone capture a difference between low activity or high activity cemeteries.