ይበልጥ በአጠቃላይ, የተፈጥሮ ሙከራዎች አንድ ጥሩ መግቢያ ነው Dunning (2012), እና Rosenbaum (2002), Rosenbaum (2009), እና Shadish, Cook, and Campbell (2001) ሙከራዎች ያለ በሲጋራና ውጤት ለመገመት ጥሩ ሐሳቦች ያቀርባሉ.
More zambiri, mawu zabwino zatsopano zachilengedwe ndi Dunning (2012), ndipo Rosenbaum (2002), Rosenbaum (2009), ndipo Shadish, Cook, and Campbell (2001) amapereka malingaliro wabwino kuyerekeza zotsatira causal popanda zatsopano.