WASHINGTON — The Census
Bureau, the authoritative source of health
insurance data for more than three decades, is changing its annual survey so
thoroughly that it will be difficult to measure the effects of President Obamafs
health
care law in the next report, due this fall, census officials said.
The changes are intended to improve
the accuracy of the survey, being conducted this month in interviews with tens
of thousands of households around the country. But the new questions are so
different that the findings will not be comparable, the officials said.
An internal Census Bureau document
said that the new questionnaire included a gtotal revision to health insurance
questionsh and, in a test last year, produced lower estimates of the uninsured.
Thus, officials said, it will be difficult to say how much of any change is
attributable to the Affordable Care Act and how much to the use of a new survey
instrument.
gWe are expecting much lower
numbers just because of the questions and how they are asked,h said Brett J.
OfHara, chief of the health statistics branch at the Census Bureau.
With the new questions, git is
likely that the Census Bureau will decide that there is a break in series for
the health insurance estimates,h says another agency document describing the
changes. This gbreak in trendh will complicate efforts to trace the impact of
the Affordable Care Act, it said.
A major goal of the law is to
increase the number of people with health insurance. The White House reported
that 7.5 million people signed up for private health plans on the new insurance
exchanges and that enrollment in Medicaid
increased by three million since October. But the administration has been unable
to say how many of the people gaining coverage were previously uninsured or had
policies canceled, so the net increase in coverage is unclear.
Health policy experts and
politicians had been assuming that the Census Bureau would help answer those
questions when it issued its report on income, poverty and health insurance,
based on the Current Population Survey. The annual report shows
the number of people with various kinds of health insurance and the number of
uninsured for the nation and for each state.
Several recent private polls,
including one by the Gallup
organization, suggest that the number of uninsured is indeed declining,
because of the Affordable Care Act and improvements in the economy.
Census officials and researchers
have long expressed concerns about the old version of insurance questions in the
Current Population Survey.
The questionnaire traditionally
used by the Census Bureau provides an ginflated estimate of the uninsuredh and
is prone to gmeasurement errors,h said a working paper by statisticians and
demographers at the agency.
In the test last year, the
percentage of people without health insurance was 10.6 percent when interviewers
used the new questionnaire, compared with 12.5 percent using the old version.
Researchers said that they had found a similar pattern in the data for different
age, race and ethnic groups.
In addition, gthe percentage of
people with private coverage was statistically higherh when the bureau tested
the new questionnaire, the working paper said. For reasons that are not clear,
people were less likely to respond when interviewers used the new
questionnaire.
Another Census Bureau paper said
git is coincidental and unfortunate timingh that the survey was overhauled just
before major provisions of the health care law took effect. gIdeally,h it said,
gthe redesign would have had at least a few years to gather base line and trend
data.h
The old questionnaire asked
consumers if they had various types of coverage at any time in the prior year.
The new survey asks if they have insurance at the time of the interview — in
February, March or April — then uses follow-up questions to find out when that
coverage began and what months it was in effect. Using this technique, census
officials believe they will be able to reconstruct the history of coverage month
by month, over a period of about 15 months, for each person in a household.
However, Mr. OfHara of the Census
Bureau said the agency was not planning to release coverage data from early this
year in its next report. Agency officials want to assess the reliability of the
monthly data, being collected this year for the first time.
The White House is always looking
for evidence to show the benefits of the health law, which is an issue in many
of this yearfs midterm elections. The Department
of Health and Human Services and the White House Council of Economic
Advisers requested several of the new questions, and the White House Office of
Management and Budget approved the new questionnaire. But the decision to make
fundamental changes in the survey was driven by technical experts at the Census
Bureau, and members of Congress have not focused on it or suggested political
motives. The new survey was conceived, in part, to reduce a kind of bias or
confusion in the old survey. When asked about their insurance arrangements in
the prior year, people tended to give answers about their coverage at the time
of the interview — forgetting, for example, if they had Medicaid for a few
months early in the prior year.
People are continually moving on
and off Medicaid rolls. The number of people who say in surveys that they have
Medicaid coverage is almost always lower than the enrollment figures reported by
federal and state agencies that administer the program.
The new survey asks people if they
have coverage through an exchange, if it has premiums and if the premiums are
subsidized.
People generally know if they have
health insurance, but not necessarily the type of coverage. A study by the
Census Bureau said that the line between public and private coverage is
blurry.
gThe same exact coverage will be
construed as private by some and public by others,h it said.
Census Bureau research in
Massachusetts found that consumers ginevitably conflate Medicaid and the
subsidized exchange.h And many people with subsidized private insurance,
purchased on the exchange, said they were receiving coverage from the government
or the state.
Such perceptions are
understandable. gExchange coverage is a hybrid, partly private and partly
government,h said Joanne Pascale, a Census Bureau researcher who helped develop
the new questionnaire.
The new survey also includes more
detailed questions about whether people were offered insurance at work and
whether they accepted it. If a worker is not in an employerfs plan, the
government asks why.
Kathleen Thiede Call, a professor
at the University of Minnesota School of Public Health, said, gThe health
insurance data reported in September of this year will not be directly
comparable to what was reported last September.h
But Ms. Call, who was consulted by
the Census Bureau, said: gI am excited about the redesign of the survey. For the
first time, we will be able to look at monthly changes in coverage over a 14- or
15-month period, which was not possible with the old version of the
survey.h