Ma'anar ƙamus na "haɗin kai kai tsaye" dangantaka ce tsakanin masu canji ko abubuwa guda biyu inda sauyin ɗaya ba ya haifar da canji na daidaici a ɗayan. Ma’ana, dangantaka ta kai tsaye tana nufin yanayin da abubuwa biyu ke da alaƙa ta wata hanya, amma dangantakar ba ta kai tsaye ko ta kai tsaye ba. Wannan kuma ana iya kiransa da “inverse correlation” ko “negative correlation,” ma’ana cewa yayin da canjin ɗaya ya ƙaru, ɗayan yana raguwa, amma ba lallai ba ne ta hanyar layi ko tsinkaya.