Transperitoneal Laparoscopic Adrenalectomy: Assessment of the Surgical Learning Curve

Table 3

Estimating a learning curve.

	(1)	(2)	(3)	(4)
Dependent variable	Operating time (min.)		Ln of blood loss (mL)
Surgeon’s experience	−12.8	−12.8	−0.59	−0.59
Ln of no. of operations	[4.88]*	[4.97]*	[0.21]**	[0.21]**
Ln of patient’s age		3.59		−0.08
		[11.84]		[0.73]
Constant	122.3 (min.)	108.4 (min.)	5.303	5.6079
	[15.4616]**	[51.0835]*	[0.6451]**	[2.9463]
Observations	44	44	44	44
𝑅-squared	0.16	0.16	0.13	0.13

Ln: natural logarithm; robust standard errors in brackets; *significant at 5%; **significant at 1%.