. Author manuscript; available in PMC: 2013 Dec 1.

Published in final edited form as: Acad Radiol. 2012 Dec;19(12):1508–1517. doi: 10.1016/j.acra.2012.09.012

Table 3.

Resources Needed for Different Study Designs

Study Design	# readers, J	# patients^*	Total # of image interpretations	# image interpretations per reader	Statistical Efficiency^**
2-block split-plot	6 (3/block)	120 (30+30)	720	120	1.0
3-block split-plot	9 (3/block)	120 (20+20)	720	80	1.2
4-block split-plot	12 (3/block)	120 (15+15)	720	60	1.33
Fully-paired A	6	60 (30+30)	720	120	0.83
Fully-paired B	6	120 (60+60)	1440	240	1.16
Unpaired-reader	12	120 (60+60)	1440	120	0.90

Total sample size (number of non-diseased and diseased patients per block)

^**

Statistical efficiency is defined as the variance of the two-block split plot design divided by the variance of the specified alternative design [19]. An efficiency >1 indicates that the variance of the 2- block split design is larger than the variance of the specified alternative design; an efficiency <1 indicates that the variance of the 2-block split design is smaller than the variance of the specified alternative. The calculations are based on the first set of model parameters in our simulation study (see Section 3).