Where are California's Uninsured Now? Wave 2 of the Kaiser Family Foundation California Longitudinal Panel Survey

This is the second in a series of surveys by the Kaiser Family Foundation (KFF) tracking the views and experiences of a group of Californians who were uninsured in the summer of 2013, prior to implementation of the ACA’s insurance market reforms and coverage expansions through Covered California and Medi-Cal. Future surveys will continue to track this group’s experiences over the course of the next year and a half. The first survey (Wave 1) was conducted from July 11-August 29, 2013, with a randomly selected group of individuals who were uninsured at the time of the interview and was paid for entirely by KFF. The current survey (Wave 2) was conducted from April 1-June 15, 2014, with the same longitudinal panel of respondents, whether they obtained coverage or remained uninsured. Both surveys were designed and analyzed by researchers at KFF. Social Science Research Solutions collaborated with KFF researchers on sample design, weighting, and supervised fieldwork. Fieldwork costs associated with Wave 2 of the survey were paid for by The California Endowment.

The Wave 1 survey was conducted among a representative random sample of 2,001 adults ages 19-64 living in California who reported having been without health insurance for at least two months at the time of the interview¹ (note: persons without a telephone could not be included in the random selection process). Computer-assisted telephone interviews conducted by landline (990) and cell phone (1,011, including 660 who had no landline telephone) were carried out in English and Spanish by SSRS. To increase efficiency in reaching this low-incidence, hard-to-reach group, both the landline and cell phone sampling frames oversampled areas with a lower-income population (since being uninsured is negatively correlated with income). The landline sample frame also oversampled households whose phone numbers were matched with directory listings indicating the presence of at least one person age 19-64 and a household income of less than $25,000. Additionally, 230 interviews (130 landline, 100 cell phone) were conducted with respondents who previously completed recent national SSRS omnibus surveys of the general public and indicated they were ages 19-64 and uninsured. These previous surveys were conducted with nationally representative, random-digit-dial landline and cell phone samples.

The current survey, Wave 2, also consisted of computer-assisted telephone interviews conducted by landline (623) and cell phone (545, including 327 who had no landline phone) in English and Spanish. Screening for Wave 2 involved verifying that the respondent had participated in Wave 1. Multiple attempts were made to reach every respondent from Wave 1 and encourage participation in Wave 2. Efforts included multiple dialing at various times of day and throughout the week, mailings and emails to those who provided such contact information, repeated dialing of non-working numbers, and attempts to find alternative phone numbers for non-working numbers.

In order to re-connect with respondents who may be more willing to complete the survey online, an abbreviated web version was introduced on May 14. The online questionnaire was offered in English and Spanish and was limited to key questions about insurance status, type of coverage, and reasons for obtaining coverage or remaining uninsured. A total of 51 respondents completed the online version of the survey.

A multi-stage weighting design was applied to ensure accurate representation of California’s nonelderly adult uninsured population prior to the ACA’s coverage expansions. The weighting process for Wave 2 involved corrections for sample design, as well as sample weighting to match the weighted Wave 2 sample to Wave 1 responses along demographic characteristics. As it did for Wave 1, the Wave 2 base weight accounted for the oversamples used in the sample design, as well as the likelihood of non-response for the sample from earlier omnibus surveys, number of eligible household members for the landline sample, and a correction to account for the fact that respondents with both a landline and cell phone have a higher probability of selection. Demographic weighting parameters for Wave 2 were based on Wave 1 weighted demographics, which were adjusted for age, education, race/ethnicity, nativity (for Hispanics only), Hispanics by gender, presence of own child in household, marital status, California region, poverty level, and phone usage. For more information on weighting and data sources, see the Wave 1 methodology. All differences referred to in the report are statistically significant. Statistical tests of significance account for the effect of weighting, and, for trend analysis, testing takes into account the survey’s panel design.

A unique consideration for surveys with a longitudinal panel design is whether those who participate in subsequent waves of the survey differ from those who refuse to participate again or are unable to be recontacted. Sixty-one percent of Wave 1 respondents completed the Wave 2 survey, and while there are some differences in the unweighted demographics of those who completed Wave 2 and the full Wave 1 sample, these differences are corrected for by weighting. As shown in the table below the total weighted distributions are similar for Wave 1 and Wave 2 for age, gender, race/ethnicity, self-reported health status, disability status, party identification, education and income. See the Wave 2 Attrition Appendix for more information on attrition.

	Unweighted			Weighted
	Wave 1	Wave 2	Percentage Point	Wave 1	Wave 2	Percentage Point
			Difference (W1 – W2)			Difference (W1 – W2)
Gender
Male	48%	44%	4	54%	53%	1
Female	52	56	-4	46	47	-1
Race/ethnicity
White	27	32	-5	26	27	-1
Black	7	8	-1	5	6	-1
Hispanic	58	52	6	56	55	1
Other Race	8	7	1	12	12	0
Age
18 to 29	23	18	5	33	32	1
30 to 39	21	21	0	24	24	0
40 to 49	22	22	0	21	21	0
50 to 64	35	39	-4	22	24	-2
Education
HS or less	57	53	4	58	57	1
Some college	28	31	-3	29	30	-1
College Grad+	15	16	-1	12	13	-1
Phone status
Landline	49	54	-5	42	44	-2
Cell	51	46	5	58	56	2
Marital status
Married	33	32	1	37	37	0
Not Married	67	68	-1	62	63	-1
Family income
<138% FPL	60	59	1	52	53	-1
138%-400% FPL	30	32	-2	36	35	1
400%+	5	5	0	7	7	0
Language of interview
English	63	68	-5	65	67	-2
Spanish	37	32	5	35	33	2
Resident status
Citizen/legal immigrant	79	82	-3	78	79	-1
Undocumented immigrant	20	16	4	21	19	2
Party identification
Republican	11	12	-1	11	12	-1
Democrat	35	36	-1	32	31	1
Independent	35	34	1	37	38	-1
Other	9	8	1	9	9	0

Another consideration for panel surveys is the potential for “sensitization effects,” that is, what effect returning to the same people about the same topics has on their experiences or views. For example, after taking the baseline survey that covered many aspects of the coverage expansions under the ACA, were people more likely to seek out information about health insurance and enroll than they would have been otherwise? While there is no direct way to measure this effect on this survey, other analyses have found that these effects are minimal and short-lived² and we do not believe they would have had a substantial impact on results presented here, particularly given all the other media coverage, advertising, and outreach targeted at this population during the fall and winter of 2013 and 2014.

The margin of sampling error including the design effect for the full sample is plus or minus 4 percentage points. For the newly insured, it is plus or minus 5 percentage points and for the remaining uninsured it is plus or minus 7 percentage points. Numbers of respondents and margin of sampling error for key subgroups are shown in the table below.

Group	N	MOSE
Total Wave 2	1,219	+/- 4 percentage points
Newly insured	740	+/- 5 percentage points
Newly insured by non-group plan	160	+/- 11 percentage points
Newly insured through Covered California	116	+/- 13 percentage points
Newly insured by Medi-Cal	368	+/- 8 percentage points
Newly insured through an employer	129	+/- 12 percentage points
Newly insured Hispanics	347	+/- 8 percentage points
Remaining uninsured	478	+/- 7 percentage points
Remaining uninsured Hispanics	284	+/- 8 percentage points
Remaining uninsured undocumented immigrants	131	+/- 12 percentage points

For results based on other subgroups, the margin of sampling error may be higher. Sample sizes and margin of sampling errors for other subgroups are available by request. Note that sampling error is only one of many potential sources of error in this or any other public opinion poll.

Some demographic measures referred to in the report were only asked during the baseline survey, such as questions about educational attainment, debilitating chronic condition, length of time uninsured, resident status, and race/ethnicity. For more information on the first wave of the Kaiser Family Foundation California Longitudinal Panel Survey visit, https://www.kff.org/health-reform/report/californias-uninsured-on-the-eve-of-aca-open-enrollment/.