The phrase "ascertained using multiple" is correct and usable in written English.
It can be used when discussing methods or processes for determining or discovering information through various means or sources.
Example: "The results of the experiment were ascertained using multiple analytical techniques to ensure accuracy."
Alternatives: "determined through various" or "established by multiple methods".
Prostate cancer was ascertained using multiple sources including hospital records.
The independent relationship of plasma biomarkers to FEV1% predicted was ascertained using multiple regression analysis.
Incident type 2 diabetes cases until 31 July 2006 were ascertained using multiple data sources, including self-report of doctor-diagnosed diabetes from the second health check or follow-up health and lifestyle questionnaires, self-report of diabetes-specific medication in either of the two follow-up questionnaires or medication brought to the follow-up health check.
As previously described (21), cases of incident type 2 diabetes were ascertained using multiple sources of evidence, including self-report (self-reported or doctor-diagnosed history of type 2 diabetes or diabetes drug use), linkage to primary or secondary care registers, medication use reported from drug registers, hospital admissions, and mortality data.
New cases of diabetes occurring up until 31 December 2005 were ascertained using multiple data sources including: self-report of doctor-diagnosed diabetes on three follow-up health and lifestyle questionnaires, i.e., a positive response to the question "Has a doctor ever told you that you have diabetes?" or self-reported diabetes medication or diabetes medication brought to the follow-up visit.
Deprivation was ascertained using the Index of Multiple Deprivation based on the participant's home address postcode.
Thermal stability of the PSMA/TiO2 hybrid was ascertained using TGA[1 10].
Technical acceptability was ascertained using recently-validated optimizations [31].
Drug resistance was ascertained using published guidelines [24].
Dilutions were ascertained using UV measurement.
Complications were ascertained using standard criteria (24).
