The frequent occurrence of residual material in terrace soils and the potential for post-depositional disturbance mean that conventional artefactual and lab-based dating methods often provide unreliable dates.
At some point Ceawlin ceased to hold the title of bretwalda, perhaps after a battle at Stoke Lyne, in Oxfordshire, which the Chronicle dates to 584, some eight years before he was deposed in 592 (again using the Chronicle's unreliable dating).
However, it has been shown that, unless particular care is taken, secondary calibration can generate internal inconsistencies leading to unreliable dates [ 64].
If last menstrual period was unknown, or considered unreliable, dating was based on clinical records of the earliest ultrasound scan or pediatric or obstetric assessment of the newborn.
The breast-cancer-specific analysis, differed in that follow-up, continued until the earliest of breast cancer diagnosis, death, loss of contact or database completion, and was left-truncated at 1960, as population rates are unreliable before this date.
The expected numbers of cancers among the first degree relatives were computed from national age- sex- and period-specific incidence rates for England and Wales, as published in Cancer in Five Continents [ 24- 30]. 1 January 1960 was used as a cut-off for entry into the cohort because national incidence rates prior to this date are unreliable.
These dates are unreliable, the team wrote, and other fossil discoveries have pushed the divergence time back sometime before six million years ago.
Yet, even though it is agreed that she was vague and unreliable in interviews about dates and places and about some names, after a number of polite but highly intensive grillings, these suspicions are roundly dismissed.
Regarding the objections based on biomolecular estimates of the hominid ape divergence as 3.5 million years ago, these dates are unreliable.
