Designed experiments remain nearly always preferred to OFAT with many types and methods available,<ref>See [[:Category: Experimental design]], at bottom.</ref> in addition to fractional factorials which, though usually requiring more runs than OFAT, do address the three concerns above.<ref name=Czitrom>[https://www.questia.com/googleScholar.qst?docId{{cite journal |last=Czitrom|first=Veronica|authorlink=5001888588 Veronica Czitrom (|year=1999)"|title=One-Factor-at-a-Time Versus Designed Experiments", |journal=American Statistician, |volume=53, |issue=2 |pages=126–131 |doi=10.]<2307/ref>2685731|jstor= 2685731}}<!--formerly http://www.amstat.org/publications/tas/czitrom.pdf--ref> One modern design over which OFAT has no advantage in number of runs is the [[Plackett-Burman design|Plackett-Burman]] which, by having all factors vary simultaneously (an important quality in experimental designs),<ref name=Czitrom /> gives generally [[Efficiency (statistics)|greater precision in effect estimation]].
