▁include ▁a ▁clear ▁statement ▁propos ing ▁the ▁anal ys es ▁to ▁be ▁undert aken . ▁P - h ack ing ▁can ▁be ▁prevent ed ▁by ▁pr er eg ister ing ▁research es , ▁in ▁which ▁research ers ▁have ▁to ▁send ▁their ▁data ▁analysis ▁plan ▁to ▁the ▁journal ▁they ▁wish ▁to ▁publish ▁their ▁paper ▁in ▁before ▁they ▁even ▁start ▁their ▁data ▁collection , ▁so ▁no ▁data ▁manip ulation ▁is ▁possible ▁( https :// os f . io ). ▁Another ▁way ▁to ▁prevent ▁this ▁is ▁taking ▁the ▁double - bl ind ▁design ▁to ▁the ▁data - analysis ▁phase , ▁where ▁the ▁data ▁are ▁sent ▁to ▁a ▁data - anal yst ▁un related ▁to ▁the ▁research ▁who ▁scr amb les ▁up ▁the ▁data ▁so ▁there ▁is ▁no ▁way ▁to ▁know ▁which ▁participants ▁belong ▁to ▁before ▁they ▁are ▁potentially ▁taken ▁away ▁as ▁out liers . ▁ ▁Clear ▁and ▁complete ▁documentation ▁of ▁the ▁experimental ▁method ology ▁is ▁also ▁important ▁in ▁order ▁to ▁support ▁rep lication ▁of ▁results . ▁ ▁Disc uss ion ▁topics ▁when ▁setting ▁up ▁an ▁experimental ▁design ▁An ▁experimental ▁design ▁or ▁random ized ▁clin ical ▁trial ▁requires ▁careful ▁consideration ▁of ▁several ▁factors ▁before ▁actually ▁doing ▁the ▁experiment . ▁An ▁experimental ▁design ▁is ▁the ▁lay ing ▁out ▁of ▁a ▁detailed ▁experimental ▁plan ▁in ▁advance ▁of ▁doing ▁the ▁experiment . ▁Some ▁of ▁the ▁following ▁topics ▁have ▁already ▁been ▁discussed ▁in ▁the ▁principles ▁of ▁experimental ▁design ▁section : ▁▁ ▁How ▁many ▁factors ▁does ▁the ▁design ▁have , ▁and ▁are ▁the ▁levels ▁of ▁these ▁factors ▁fixed ▁or ▁random ? ▁