However, this sequence of events would not ascertain with certainty that an infarct was the underlying etiology, as each particular hallucination/headache episode would certainly not result in an infarct indefinitely.
"As it is impossible for me to ascertain with certainty who these anonymous writers are," he wrote, "I beg to suggest that another order be published holding the editors responsible for its infraction".
DNA damage is difficult to ascertain with certainty.
Although we cannot ascertain with certainty how many exons and partial exons each sequence tag spans, we expect that they too generate multiple localizations to a single exon.
Fourth, the outcomes were measured at one point in time so it is not possible to ascertain with certainty the direction of relationships reported.
With such losses to follow-up it was hard to ascertain with certainty what the true outcomes were at study completion for the patients in these trials.
In some cases, it was difficult to ascertain with certainty which recommendations in each report were based on research evidence, which on expert opinion and which on experience.
Despite the improvements in VTE risk assessment and prevention discussed above, it remains difficult to ascertain with certainty if monetary incentives were the driving force behind the significant changes in the percentages of patients risk assessed between 2009 and 2010 in each hospital.
The techniques invoked in the name of "evidence-based" decision-making require a positivistic reliance on "the evidence" in its epistemological promise to ascertain truth or certainty by examination of the evidence.
For example, in Florida, "If we were omniscient, or if time were of no moment, we could probably do the fair thing and ascertain with near certainty how everyone voted," Professor Gillers said.
And although many of the non-experimental studies are based on state-of-the-art methodologies, it is typically hard to ascertain with absolute certainty that the results really capture the causal effects of interest, and not the unobserved sorting into the various types of programs.
