Ubaid: the villages before the first cities
Ubaid settlements came before Mesopotamia’s large cities. Two published timelines for the period differ, and averaging them would hide the disagreement.

Settlements before the first cities
The Ubaid period describes the village communities of southern Mesopotamia before the urban growth of Uruk. The Cambridge chapter attached to this subject frames the period at about 5300 to 4100 BCE and treats it as the long background to the birth of the state. Cambridge University Press ↗
Two ranges, one subject
An earlier research seed modeled the same period as beginning around 6500 BCE. Rather than silently replacing one number with another, the research record keeps both ranges as separate candidates and notes that the source basis for the earlier start remains unresolved.
Why do the Ubaid dates differ?
When two reputable syntheses disagree, look for the reason: a different regional definition, a different phase nomenclature, or a newer dating series. A rule used here is not to average competing ranges. Compare the definitions first.
What does the date actually date?
Which came first in your reading: the number or the definition of what it dates? Try reading the chapter with that order reversed.