. Author manuscript; available in PMC: 2016 Dec 8.

Published in final edited form as: Gynecol Oncol. 2015 Sep 24;139(3):495–499. doi: 10.1016/j.ygyno.2015.09.015

Table 2.

Statistics and O/E^* by hospital case volume.

Hospital annual case volume	n	%	Mean O/E	Standard deviation	Minimum	Maximum
≤2 cases per year	148	36.54	0.73	0.67	0.00	2.97
2.001–5 cases per year	134	33.09	0.84	0.38	0.00	2.44
5.001–9 cases per year	54	13.33	0.93	0.29	0.33	1.65
9.001–19.999 cases per	57	14.07	1.00	0.27	0.38	1.55
≥20 cases per year	12	2.96	1.22	0.27	0.80	1.77

Observed-to-expected ratio.