We began with a gathering of nationally known scholars and practitioners to discuss the ways in which a study of social trust could expand our understanding of the state of social capital in Philadelphia. Following this meeting, we turned to Philadelphians themselves for their feelings about trust and patterns of engagement in their own lives, convening six focus groups with a cross-section of residents and community leaders from the Philadelphia area.
A large telephone survey of Philadelphians was then conducted, as well as a smaller companion national survey. The Philadelphia survey results are based on telephone interviews conducted under the direction of Princeton Survey Research Associates among a representative sample of 2,517 adults living in Philadelphia and the adjoining metropolitan counties of Bucks, Chester, Delaware and Montgomery. The interviews were conducted from November 13 through December 8, 1996. For results based on the total sample, one can say with 95 percent confidence that the error attributable to sampling is plus or minus 2 percentage points. In addition to sampling error, question wording and practical difficulties in conducting telephone surveys can introduce error or bias into the finding of opinion polls.
The sample of telephone numbers used for this survey was a random digit dial sample drawn from telephone exchanges serving the targeted five-county area and was designed to provide an accurate representation of all population subgroups. At least four attempts were made to complete an interview at every sampled telephone number. The calls were staggered over times of day and days of the week to maximize the chances of making a contact with a respondent. Interviewers used a systematic respondent selection procedure to select an adult within contacted households containing more than one resident 18 years of age or older.
Demographic weighting was used to bring the characteristics of the sample into alignment with the demographic characteristics of the adult population of Philadelphia and the four adjoining metropolitan counties of Bucks, Chester, Delaware and Montgomery. The characteristics of survey respondents (age, gender, race , education and county of residence) were compared to the targets for adults 18 or older, and weights were calculated to bring the sample into conformity with the target distributions.
Results from the national survey are based on telephone interviews conducted under the direction of Princeton Survey Research Associates among a nationwide sample of 1,003 adults, 18 years of age or older, during the period February 6 – 9, 1997. For results based on the total sample, one can say with 95% confidence that the error attributable to sampling and other random effects is plus or minus 4 percentage points.
The sample for the national survey was a random digit sample of telephone numbers selected from telephone exchanges in the continental United States. The exchanges were selected with probabilities proportional to their size. The sample was released for interviewing in replicates. The sample data were weighted in analysis so as to compensate for known biases in survey-designed estimates due to non-response. The demographic weighting parameters were derived from a special analysis of the most recently available Census Bureau Current Population Survey (March 1994).
