, ▁one ▁recommendation ▁is ▁that ▁an ▁appropri ately ▁s ized ▁orthogonal ▁array ▁be ▁randomly ▁selected ▁from ▁those ▁available , ▁then ▁random ize ▁the ▁run ▁order . ▁ ▁Qu ality ▁control ▁ ▁Orth ogonal ▁arrays ▁played ▁a ▁central ▁role ▁in ▁the ▁development ▁of ▁Tag uch i ▁methods ▁by ▁Gen ichi ▁Tag uch i , ▁which ▁took ▁place ▁during ▁his ▁visit ▁to ▁Indian ▁Statist ical ▁Institute ▁in ▁the ▁early ▁ 1 9 5 0 s . ▁His ▁methods ▁were ▁successfully ▁applied ▁and ▁adopted ▁by ▁Japanese ▁and ▁Indian ▁indust ries ▁and ▁subsequently ▁were ▁also ▁emb rac ed ▁by ▁US ▁industry ▁al beit ▁with ▁some ▁res erv ations . ▁ ▁Test ing ▁Orth ogonal ▁array ▁testing ▁is ▁a ▁black ▁box ▁testing ▁technique ▁which ▁is ▁a ▁system atic , ▁statistical ▁way ▁of ▁software ▁testing . ▁It ▁is ▁used ▁when ▁the ▁number ▁of ▁inputs ▁to ▁the ▁system ▁is ▁relatively ▁small , ▁but ▁too ▁large ▁to ▁allow ▁for ▁exhaust ive ▁testing ▁of ▁every ▁possible ▁input ▁to ▁the ▁systems . ▁It ▁is ▁particularly ▁effective ▁in ▁finding ▁errors ▁associated ▁with ▁fault y ▁logic ▁within ▁computer ▁software ▁systems . ▁Orth ogonal ▁arrays ▁can ▁be ▁applied ▁in ▁user ▁interface ▁testing , ▁system ▁testing , ▁regression ▁testing ▁and ▁performance ▁testing . ▁The ▁permut ations ▁of ▁factor ▁levels ▁compr ising ▁a ▁single ▁treatment ▁are ▁so ▁chosen ▁that ▁their ▁responses ▁are ▁un cor related ▁and ▁hence ▁each ▁treatment ▁gives ▁a ▁unique ▁piece ▁of ▁information . ▁The ▁net ▁effect ▁of ▁organ izing ▁the ▁experiment ▁in ▁such ▁treat ments ▁is ▁that ▁the ▁same ▁piece ▁of ▁information ▁is ▁gathered ▁in