Use of references was categorized as: references in text (for example when a particular drug was recommended in the text and a trial of this drug was cited), references, but not in text (when the references were at the end of the guideline only), and no references.
All adverse events were categorized as mild.
Objective image quality (IQA) assessment methods can be categorized as full reference (FR), reduced reference (RR), and no reference (NR) depending on whether a reference, partial information about a reference, or no reference is used for calculation.
Race/ethnicity was categorized as white (reference), African American, Hispanic, and other.
Those that did not possess confirmed identity were categorized as unique reference FLcDNAs.
Age was fitted as a continuous variable, while smoking was categorized as Never (reference category), Ex-smoker, <15 cigarettes/day, and ≥ 15 cigarettes/day.
For speech technologies, models can be further categorized as full-reference (also known as double-ended, intrusive) or no-reference (single-ended, non-intrusive), depending on the need, or not, of a reference signal, respectively.
Consequently, genes with fold changes < 1.46 from zero across all 384 arrays were categorized as candidate endogenous reference genes and were ranked according to ascending values of SD of Log ratio (Table 1).
The following covariates were considered in the regression: mechanism of injury (motor vehicle-related injury, other), age in years categorized (16 25 as reference group, 26 45, 46 and older), gender, education at follow-up categorized (below high school, high school, college and above as the reference group), an indicator for transfer to surgery from the ED,ISS, and RTS (Lichtveld et al. 2008).
