For questions with pre-coded responses, the system only permits answers with-
in a specified range; for example, if a question has three possible answer choices (e.g.,
"Agree", "Disagree", "Not sure"), the system will only accept coded responses corre-
sponding to these choices. All data is tabulated, checked for internal consistency and
processed by computer. A series of computer-generated tables is then produced for
each sample group showing the results of each survey question, both by the total
number of respondents and by important subgroups.
To maintain the reliability and integrity in the sample, the following procedures
are used:
1. Password protection: Each invitation contains a password that is uniquely
assigned to that e-mail address. A respondent is required to enter the pass-
word at the beginning of the survey to gain access into the survey. Password
protection ensures that a respondent completes the survey only one time.
2. Reminder invitations: To increase the number of respondents in the survey
and to improve overall response rates, up to two additional reminder invita-
tions are typically mailed at 2-4 day intervals to those respondents who have
not yet participated in the survey.
3. Summary of the survey findings: To increase the number of respondents in
the survey and to improve overall response rates, respondents are often pro-
vided with a summary of some of the survey responses. This too is done via
the Internet. Respondents are sent an email that provides them access to a
web site that will contain the survey findings. As with the survey itself, this is
a password-protected site that is accessible for a limited period (1-2 weeks).
The data processing staff performs machine edits and additional cleaning for the
entire data set. Our edit programs act as a verification of the skip instructions and
other data checks that are written into the online program. The edit programs list
any errors by case number, question number and type. These were then resolved by
senior EDP personnel, who inspected the original file and made appropriate correc-
tions. Complete records were kept of all such procedures.
Weighting of Student Data
Data were weighted to reflect the national population of public school students in
grades 7 through 12 for key demographic variables (grade, gender, race and region).
Demographic weights were based on data from the U.S. National Center of
Education Statistics. In addition, data collected online were weighted to key behav-
ioral and attitudinal variables to align it with the data collected using the school
methodology and to represent two-thirds of the total interviews.
Teacher Sample
The survey included a total of 1010 interviews with a nationally representative sam-
ple of current public school teachers of grades 7 through 12 throughout the conti-
nental United States. Interviews averaged 15 minutes in length and were conducted
between April 12, 2000 and May 31, 2000. Teachers were given the option of partic-
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