Table 3.

Risk Selection Based on Medical Care Use in Round 1 for Enrollees with and without a Choice of Plan Types in Round 1

Variable	Coefficient	Std. Error	Coefficient	Std. Error	Coefficient	Std. Error
Non-HMO, no choice in round 1
Non-HMO in round 2 (control)	1,241**	488	1,793**	252	764	710
HMO in round 2 (switcher)	1,658**	551	2,084**	342	1,072	713
Non-HMO, with choice in round 1
Non-HMO in round 2 (control)	1,647**	468	2,064**	251	982	696
HMO in round 2 (switcher)	1,121**	478	1,626**	239	695	702
HMO, no choice in round 1
HMO in round 2 (control)	1,475**	503	1,977**	284	806	724
Non-HMO in round 2 (switcher)	2,475**	598	2,898**	429	1,691**	798
HMO, choice in round 1
HMO in round 2 (control)	1628**	474	2,078**	215	976	702
Non-HMO in round 2 (switcher)	1752**	501	2,239**	314	1,037	727
Female			633**	110	594**	105
Age (56–65 is omitted group)
Under 2 years of age			3,899**	694	4,904**	808
Between 2 and 17			−1,428**	265	−515	487
Between 18 and 40			−756**	274	−185	298
Between 40 and 55			−852**	271	−547*	282
Other potentially observable characteristics included?	NO		NO		YES
Number of observations	6,235		6,235		6,235

Notes: Dependent variable is medical care use in round 1, measured in dollars.

^**=significantly different from zero at the 5-percent level;

^*=significantly different from zero at the 10-percent level. Bold coefficients indicate that the expenditure difference in round 1 between the people switching plan types and those remaining in a particular plan type is significantly different from zero at the 5-percent level. All specifications include indicator variables for the site of the survey (usually a metropolitan statistical area). Additional potentially observable enrollee and employer characteristics include: self-reported health, marital status, children, race, education, household income, type of employer (i.e., private or government), and number of employees at the person's firm. The constant is omitted. Sample includes people who had a choice between an HMO and a non-HMO plan in round 2.