Income Data for Policy Analysis: A Comparative Assessment of Eight Surveys. Uninsured at a Point in Time

12/23/2008

Three of the surveys provide estimates of health insurance coverage and the uninsured at a point in time. The NHIS measures coverage at the time of the interview, while SIPP and MEPS obtain estimates of coverage by month from interviews that ask about the previous several months.34 In the tables presented in this section, the NHIS estimates represent an average of respondents’ reports over the 2003 calendar year while the SIPP and MEPS estimates refer to December 2002.

Estimates of the proportion of the population that was without health insurance coverage at a point in time range from 14.6 percent for the NHIS to 16.8 percent for MEPS, with SIPP falling between these two at 15.3 percent (Table IV.26).35 Despite differences in the surveys’ estimates of the distribution of the population by poverty level and the fact that income is measured over a period of a year while health insurance coverage refers to a point in time at the end of that year (SIPP and MEPS) or 1 to 12 months later (NHIS), uninsured rates across the three surveys show very similar patterns by poverty relative. Rates of 28 to 31 percent among the poor decline to about 5 to 8 percent among those with incomes above 400 percent of poverty. Estimates of the number of uninsured persons below 200 percent of poverty are exceedingly close in the three surveys, with a range of 24.7 million (MEPS) to 25.1 million (NHIS).

Policy analysis of the uninsured often excludes the elderly population, whose coverage rates are so high that estimates of their uninsured rates are dominated by measurement error. Estimates of the uninsured rate among the elderly range from 0.5 percent for MEPS to 0.9 percent for SIPP and 1.1 percent for NHIS (Table IV.27). Both SIPP and NHIS show an uninsured rate of about 3 percent among the poor with declining rates by poverty relative while MEPS shows no distinct pattern.

For the nonelderly population as a whole, the patterns among the three surveys are very similar to those for all persons, except that the uninsured rates are about 2 percentage points higher. MEPS is again highest at 19.0 percent, followed by SIPP at 17.2 percent and NHIS at 16.4 percent (Table IV.28). Uninsured rates by poverty relative decline similarly across the three surveys.

TABLE IV.26

PERSONS UNINSURED AT A POINT IN TIME BY POVERTY RELATIVE SIPP, MEPS, AND NHIS
Population and Poverty Relative SIPP MEPS NHIS
All Persons (millions)
All Persons 281.08 283.30 283.71
Poverty Relative(Under 100%) 33.25 35.35 41.58
Poverty Relative(100% to under 200%) 56.25 52.14 53.91
Poverty Relative(200% to under 400%) 98.37 89.80 87.06
Poverty Relative(400% and over) 93.22 106.02 101.16
Uninsured Persons (millions)
All Persons 42.88 47.45 41.32
(Poverty Relative)Under 100% 10.36 10.12 11.77
(Poverty Relative)100% to under 200% 14.56 14.60 13.34
(Poverty Relative)200% to under 400% 13.50 14.56 11.37
(Poverty Relative)400% and over 4.46 8.18 4.84
Percent Uninsured
All Persons 15.3 16.8 14.6
(Poverty Relative)Under 100% 31.2 28.6 28.3
(Poverty Relative)100% to under 200% 25.9 28.0 24.7
(Poverty Relative)200% to under 400% 13.7 16.2 13.1
(Poverty Relative)400% and over 4.8 7.7 4.8

Source:   Mathematica Policy Research, from tabulations of the 2001 SIPP panel, the 2002 Full-year Consolidated MEPS-HC, and the 2003 NHIS. Note: Poverty status is for calendar year 2002, and uninsured status is in December 2002 or average monthly in 2003 (NHIS).

TABLE IV.27

ELDERLY UNINSURED AT A POINT IN TIME BY POVERTY RELATIVE: SIPP, MEPS, AND NHIS
Population and Poverty Relative SIPP MEPS NHIS
All Persons (millions)
All Persons 65 and Older 33.95 34.15 34.22
(Poverty Relative)Under 100% 3.03 3.84 3.76
(Poverty Relative)100% to under 200% 8.56 9.72 9.10
(Poverty Relative)200% to under 400% 13.52 10.37 12.96
(Poverty Relative)400% and over 8.84 10.22 8.40
Uninsured Persons (millions)
Persons 65 and Older 0.31 0.16 0.36
(Poverty Relative)Under 100% 0.10 0.02 0.10
(Poverty Relative)100% to under 200% 0.06 0.07 0.12
(Poverty Relative)200% to under 400% 0.13 0.02 0.09
(Poverty Relative)400% and over 0.02 0.05 0.05
Percent Uninsured
Persons 65 and Older 0.9 0.5 1.1
(Poverty Relative)Under 100% 3.2 0.5 2.8
(Poverty Relative)100% to under 200% 0.7 0.8 1.3
(Poverty Relative)200% to under 400% 0.9 0.2 0.7
(Poverty Relative)400% and over 0.3 0.5 0.6

Source:   Mathematica Policy Research, from tabulations of the 2001 SIPP panel, the 2002 Full-year Consolidated MEPS-HC, and the 2003 NHIS.Note:  Poverty status is for calendar year 2002, and uninsured status is in December 2002 or average monthly in 2003 (NHIS).

TABLE IV.28

NONELDERLY UNINSURED AT A POINT IN TIME BY POVERTY RELATIVE: SIPP, MEPS, AND NHIS
Population and Poverty Relative SIPP MEPS NHIS
All Persons (millions)
All Persons under 65 247.13 249.14 249.49
(Poverty Relative)Under 100% 30.21 31.50 37.82
(Poverty Relative)100% to under 200% 47.69 42.42 44.81
(Poverty Relative)200% to under 400% 84.85 79.42 74.10
(Poverty Relative)400% and over 84.37 95.80 92.76
Uninsured Persons (millions)
Persons under 65 42.58 47.30 40.96
(Poverty Relative)Under 100% 10.27 10.10 11.67
(Poverty Relative)100% to under 200% 14.50 14.52 13.22
(Poverty Relative)200% to under 400% 13.37 14.54 11.27
(Poverty Relative)400% and over 4.44 8.13 4.79
Percent Uninsured
Persons under 65 17.2 19.0 16.4
(Poverty Relative)Under 100% 34.0 32.1 30.9
(Poverty Relative)100% to under 200% 30.4 34.2 29.5
(Poverty Relative)200% to under 400% 15.8 18.3 15.2
(Poverty Relative)400% and over 5.3 8.5 5.2

Source:   Mathematica Policy Research, from tabulations of the 2001 SIPP panel, the 2002 Full-year Consolidated MEPS-HC, and the 2003 NHIS. Note: Poverty status is for calendar year 2002, and uninsured status is in December 2002 or average monthly in 2003 (NHIS).

When we separate children from nonelderly adults, however, we find a shift in SIPP relative to the other two surveys. SIPP finds the highest uninsured rate among children at 14.7 percent, followed by MEPS at 12.5 percent and NHIS at 9.8 percent (Table IV.29). SIPP differs most from the other two surveys among poor children. SIPP finds an uninsured rate of nearly 23 percent among poor children compared to 14.2 percent for MEPS and 16.7 percent for NHIS. The SIPP finding may be an artifact of how SIPP collects health insurance coverage for children versus adults. Children under 15 are not defined as respondents in the SIPP, and this has implications for how their data are collected. For persons 15 and older, the survey goes through the household person by person to obtain reported coverage. Children’s coverage is obtained solely by asking who else in the household has coverage under each reported plan or source. This may lend itself to periodic omissions of individual children from lists of those covered. Whatever the reason, SIPP finds 1.9 million more uninsured children below 200 percent of poverty (6.7 million) than either MEPS or NHIS (4.7 and 4.8 million).

Among nonelderly adults, SIPP’s position reverses, with SIPP having the lowest uninsured rate (18.3 percent) among the three surveys (Table IV.30). NHIS is marginally higher at 19.1 percent while MEPS finds 21.6 percent without coverage. Again, however, the three surveys show similar patterns of decline by poverty relative, with MEPS being highest in every category of relative income.

One other point about income and the uninsured should be noted. Among children, MEPS shows a higher uninsured rate between 100 and 200 percent of poverty than below poverty while the other two surveys show marginally higher uninsured rates among the poor. Among nonelderly adults, all three surveys show higher uninsured rates among the poor than among the near poor. The difference between children and adults in all three surveys reflects the impact of public coverage, which benefits children more than nonelderly adults and largely offsets or perhaps more than offsets the adverse effects of declining income on the availability of coverage from private sources. We see this in all three surveys, albeit to different degrees.

TABLE IV.29

CHILDREN UNINSURED AT A POINT IN TIME BY POVERTY RELATIVE: SIPP, MEPS, AND NHIS
Population and Poverty Relative SIPP MEPS NHIS
All Persons (millions)
All Children under 18 71.36 71.80 71.73
(Poverty Relative)Under 100% 12.78 12.47 14.29
(Poverty Relative)100% to under 200% 17.72 15.47 15.41
(Poverty Relative)200% to under 400% 24.58 24.49 21.67
(Poverty Relative)400% and over 16.28 19.36 20.36
Uninsured Persons (millions)
Children under 18 10.47 8.98 7.04
(Poverty Relative)Under 100% 2.92 1.77 2.38
(Poverty Relative)100% to under 200% 3.76 2.97 2.39
(Poverty Relative)200% to under 400% 2.95 2.90 1.73
(Poverty Relative)400% and over 0.84 1.34 0.54
Percent Uninsured
Children under 18 14.7 12.5 9.8
(Poverty Relative)Under 100% 22.8 14.2 16.7
(Poverty Relative)100% to under 200% 21.2 19.2 15.5
(Poverty Relative)200% to under 400% 12.0 11.8 8.0
(Poverty Relative)400% and over 5.2 6.9 2.6

Source:   Mathematica Policy Research, from tabulations of the 2001 SIPP panel, the 2002 Full-year Consolidated MEPS-HC, and the 2003 NHIS. Note:Poverty status is for calendar year 2002, and uninsured status is in December 2002 or average monthly in 2003 (NHIS).

TABLE IV.30

NONELDERLY ADULTS UNINSURED AT A POINT IN TIME BY POVERTY RELATIVE: SIPP, MEPS, AND NHIS
Population and Poverty Relative SIPP MEPS NHIS
All Persons (millions)
All Persons 18 to 64 175.77 177.34 177.76
(Poverty Relative)Under 100% 17.44 19.03 23.53
(Poverty Relative)100% to under 200% 29.97 26.95 29.40
(Poverty Relative)200% to under 400% 60.27 54.93 52.42
(Poverty Relative)400% and over 68.09 76.43 72.40
Uninsured Persons (millions)
Persons 18 to 64 32.10 38.32 33.93
(Poverty Relative)Under 100% 7.35 8.33 9.29
(Poverty Relative)100% to under 200% 10.74 11.55 10.84
(Poverty Relative)200% to under 400% 10.42 11.64 9.55
(Poverty Relative)400% and over 3.59 6.79 4.26
Percent Uninsured
Persons 18 to 64 18.3 21.6 19.1
(Poverty Relative)Under 100% 42.2 43.8 39.5
(Poverty Relative)100% to under 200% 35.8 42.9 36.9
(Poverty Relative)200% to under 400% 17.3 21.2 18.2
(Poverty Relative)400% and over 5.3 8.9 5.9

Source:   Mathematica Policy Research, from tabulations of the 2001 SIPP panel, the 2002 Full-year Consolidated MEPS-HC, and the 2003 NHIS. Note: Poverty status is for calendar year 2002, and uninsured status is in December 2002 or average monthly in 2003 (NHIS).

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