In this image, the universal set U (the entire rectangle) is dichotomized into the two sets A (in pink) and its complement Ac (in grey).

A dichotomy i/ is a partition of a whole (or a set) into two parts (subsets). In other words, this couple of parts must be

Such a partition is also frequently called a bipartition.

The two parts thus formed are complements. In logic, the partitions are opposites if there exists a proposition such that it holds over one and not the other.

Treating continuous variables or multicategorical variables as binary variables is called dichotomization. The discretization error inherent in dichotomization is temporarily ignored for modeling purposes.


The term dichotomy is from the Greek language Greek: διχοτομία dichotomía "dividing in two" from δίχα dícha "in two, asunder" and τομή tomḗ "a cutting, incision".

Other Languages
العربية: ديكوتومية
български: Дихотомия
bosanski: Dihotomija
català: Dicotomia
čeština: Dichotomie
dansk: Dikotomi
Deutsch: Dichotomie
español: Dicotomía
Esperanto: Diĥotomio
euskara: Dikotomia
فارسی: دیکوتومی
français: Dichotomie
한국어: 이분법
हिन्दी: द्विभाजन
hrvatski: Dihotomija
Bahasa Indonesia: Dikotomi
íslenska: Tvískipting
italiano: Dicotomia
עברית: דיכוטומיה
қазақша: Дихотомия
Nederlands: Dichotomie
norsk: Dikotomi
polski: Dychotomia
português: Dicotomia
română: Dihotomie
русский: Дихотомия
српски / srpski: Dihotomija
srpskohrvatski / српскохрватски: Dihotomija
suomi: Dikotomia
svenska: Dikotomi
українська: Дихотомія
中文: 二分法