I. INTRODUCTION
The Healthy New Jersey 2010 State Health Issues Opinion Survey was developed by
The Eagleton Institute's Center for Public Interest Polling in consultation with
representatives from NJDHSS. The main objective of the survey is to provide
information on the public's top health concerns.
II. QUESTIONNAIRE DEVELOPMENT
Eagleton conducted a similar survey in 1991 for NJDHSS and that instrument was
used as the basis for the current survey. Representatives of NJDHSS also
proposed additional questions to be addressed in the study. The questionnaire
was then drafted and refined by the Eagleton research staff. The draft
questionnaire was pretested with a random group of New Jersey residents and
modifications were made to the survey instrument in order to increase the
understandability and accuracy of the questions asked.
Besides the series of questions on identifying state health concerns and the
role of different entities in addressing those concerns, some basic demographic
information was obtained from all study participants in order to provide more
detailed analysis of the data.
The final version of the questionnaire was programmed into a CATI (Computer
Assisted Telephone Interview) system. The CATI system enables the interviewer
to accurately skip over certain questions which may be irrelevant to a
particular study participant, while retaining the flow and integrity of the
interview process.
III. SAMPLE DESIGN
A random proportional probability sample was used to select the 804 New Jersey
residents 18 years of age and older who were contacted to participate in this
study. The sample was designed to make sure that each of the state's 21
counties was proportionately represented and that an equal number of men and
women were interviewed. The three-digit exchange was used to match telephone
numbers and geographic areas. The remaining four digits were randomly selected.
This procedure insures that those with unlisted or new telephone numbers are
included in the sample. Each working phone number was called a minimum of three
times, at different times of the week, in an effort to reach people who were
infrequently at home.
IV. WEIGHTING
While those interviewed in a survey ideally will have the same characteristics
as the population they represent, samples frequently may under-represent groups
that are more difficult to interview, such as the elderly or those with less
than a high school education. To correct this imbalance, a statistical
technique known as "weighting" is used. The weighting procedure compares New
Jersey population figures for age and education based on census data with those
of the sample. When there is significant difference between these two figures,
the sample is weighted so it more accurately reflects the population of the
state. For example, if census figures show 39 percent of New Jerseyans 18 years
and older to have a high school education, and the sample consists of 32 percent
with a high school education, each respondent in this category would be counted
as 1.21 persons to adjust for this difference.
V. SAMPLING ERROR
The percentages obtained in a sample survey are estimates of what the
distribution of responses would be if the entire population had been surveyed.
"Sampling error" is a statistical term which describes the probable difference
between interviewing everyone in a given population and a sample drawn from that
population. For example, the sampling error associated with a sample of 804
persons is +/-3.5 percent at a 95 percent confidence interval. Thus, if 47
percent of those in a sample of 804 are found to agree with a particular
statement, the percentage of agreement within the population from which the
sample was drawn would be between 43.5 and 50.5 percent (47 +/-3.5%) 95 times out
of 100.
Sampling error increases as the sample size is reduced. For, example, if
statements are made based on a sub-group of 400 persons, the sampling error is
+/-5 percent. This fact must be kept in mind when comparing the responses of
different groups within a sample (e.g. men compared with women). Figure 1 in
this appendix shows the relationship between sample (or group) size and sampling
error.
Readers should note that sampling error does not take into account other
possible sources of error inherent in any study of public opinion.
VI. DATA COLLECTION
The study involved CATI interviews with a random probability sample of 804 New
Jersey residents 18 years of age and older. The CATI interviews were conducted
by telephone between May 4 and May 11, 1999 by experienced professional
interviewers who were trained and monitored by the Eagleton research staff.
VII. DATA PROCESSING AND ANALYSIS
The CATI system generates a computer readable data file which reduces the amount
of error inherent in the coding and entry of data recorded on paper
questionnaires. An SPSS (Statistical Package for the Social Sciences) computer
file was developed to process the CATI information. The SPSS system enabled the
Eagleton research staff to integrate the survey data so that it could be
presented in aggregate form.
VIII. REGIONAL CLASSIFICATIONS
Region is classified according to county boundaries:
North -- Bergen, Essex, Hudson, Morris, Passaic, Sussex, Union, and Warren
Central -- Hunterdon, Mercer, Middlesex, Monmouth, and Somerset
South -- Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, Ocean, and Salem
Type of Community: All municipalities in the state have been classified into
one of five groups or "types," based on location, settlement patterns,
population density and growth.
Major Urban Centers -- New Jersey's largest cities: Newark, Jersey City,
Paterson, Elizabeth, Trenton, and Camden.
Urban Centers & Surrounding Areas -- This category is generally based on
the cities of the state over 25,000, but also includes densely populated
suburbs of urban areas which also have similar socio-economic
characteristics. For example, all of Hudson county (outside of Jersey
City), and much of Union, eastern Essex and southern Bergen counties are
included in this category.
Older Towns & Suburbs -- This category includes two types of
municipalities: urban suburbs which are not as densely populated and/or
have significantly higher socio-economic characteristics than the nearby
urban center; and densely populated towns which are not near urban centers,
and have not experienced major development in the past decade.
New Suburbs -- These are primarily suburban areas which are "outside
central city" proportions of the Census Bureau's Standard Metropolitan
Statistical Areas and have continued to experience growth in the past 20
years. These municipalities are usually within a short distance of urban
centers.
Rural -- This includes municipalities not in any of the categories above.
These are small communities with scattered populations and somewhat denser
small towns which are surrounded by rural areas.
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