Table 5:

Regression Results for Other Practice Patterns, NAMCS 2002–2004 and 2006–2009

	Number of Tests	Time Spent	Age of Active Ingredients	Number of Branded Drugs
	(1)	(2)	(3)	(4)
Age 65 * Year 2006	−0.052	2.892	4.861	0.307
	(0.123)	(1.788)	(9.654)	(0.226)
Order of Polynomial	3	3	3	3
R-squared	0.322	0.070	N/A	0.135
Observations	26,474	26,474	54,132	26,474
Age 65 * Year 2006	0.006	4.332	−9.639	0.302
	(0.150)	(2.748)	(11.519)	(0.272)
Order of Polynomial	4	4	4	4
R-squared	0.322	0.071	N/A	0.136
Observations	26,474	26,474	54,132	26,474

^1.Control variables for regressions include a dummy for year 2006 or later, age 65 or over, a polynomial control for age in days and full interaction with the age 65 dummy and year2006 dummy, patient sex, race, Charlson index dummies, disease category by primary diagnosis codes, visit quarter, physician specialty type, whether it is a solo practice or not, electronic medical records utilization, metropolitan statistical area (MSA) status and dummy for revenue from Medicare patients above median.

^2.The R-squared statistics is not available for regressions with the dependent variable consisting of the age of active ingredients because these are censored regressions; the date of approval for drugs in the Orange Book database is only available after 1982.

^3.***Significant at the 1% level (two-tail test); ** Significant at the 5% level (two-tail test); * Significant at the 10% level (two-tail test).