ODM2 Aggregation Statistic Controlled Vocabulary ODM2 Working Group A vocabulary for describing the calculated statistic associated with recorded observations. The aggregation statistic is calculated over the time aggregation interval associated with the recorded observation. Standard error of the mean The standard error of the mean (SEM) quantifies the precision of the mean. It is a measure of how far your sample mean is likely to be from the true population mean. It is expressed in the same units as the data. See https://en.wikipedia.org/wiki/Standard_error