Table 1. Outcome measures, their level of measurement (patient or vertebral), definition and the statistical methods applied to analyze intra- and interobserver agreement and reliability.

Level	Outcome	Definition	Measure
			Agreement	Reliability
Patient	Fracture present	Fracture present (yes/no)	% absolute agreement	Cohen's kappa
	Worst fracture grade	Grade 0 = <20% height loss	% absolute agreement	Weighted kappa*
		Grade 1 = 20–25% height loss
		Grade 2 = 25–40% height loss
		Grade 3 = >40% height loss
	Cumulative fracture grade	Sum of all grades for all fractures, continuous scale	95% Limits of Agreement	Intraclass Correlation Coefficient
Vertebral	Height loss	Measured height loss, expressed as percentage**	95% Limits of Agreement	Intraclass Correlation Coefficient
	Fracture present	Fracture present (yes/no)	% absolute agreement	Cohen's kappa

^*Square weighted Cohen's Kappa.

^**The fractured vertebra is compared to the nearest unfractured vertebra, with preference given to vertebrae cranial to (above) the fractured vertebra. The percentage of the worst height loss of each fractured vertebra (either anterior, middle or posterior part of the vertebral corpus), is given (see Figure 1).