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Omnibus Survey Household Survey Results Month Specific Information November 2001

Omnibus Survey
Household Survey Results
Month Specific Information
November 2001

This report presents the results of the November 2001 Household Survey. Each monthly survey will contain a set of core questions that are based on critical information needs within DOT. In addition, supplemental questions will be included each month that correspond to one of DOT's five strategic goals: safety, mobility, economic growth, human and natural environment, and security. Finally, specific questions posed by the various DOT modes will be included in each survey and will vary from month to month.

The November 2001 survey collected data between November 3, 2001 and November 11, 2001. Data were collected from households in the U.S. using a Random-Digit-Dialed telephone methodology. The final completed sample size is 1,039 cases, and the total number of variables in the public-use dataset is 239. The data were collected by M. Davis and Company, under contract with the BTS.

Sample Telephone Number Selection

There were 11,271 telephone numbers purchased for the November 2001 survey. A total of 7,117 of these numbers were identified as working residential numbers and were divided into 72,72 replicates. Each replicate contained approximately 100 households. Four of the replicates were used to conduct a pretest and 44 replicates were used for the actual interviewing. Twenty-two (22) (includes the 4 replicates used for the pretest) of the 72,72 replicates were not utilized in the actual interviewing, resulting in 4,614 numbers being released for use by the telephone interviewers.

For this month's survey, the total number of telephone numbers in the sampling frame, N, is 260,828,700. The total number of telephone numbers in the sample (numbers dialed) is 4,394.

Specific Weight Adjustment for Households with Multiple Telephone Numbers

Some households have multiple telephone lines for voice communication.

The table below provides summary statistics for the number of telephone lines in the monthly sampled households.

Table 1: Number of Telephone Lines per Household

  Value
Mean 1.194
Standard deviation 0.514
Minimum     1
25th percentile     1
Median     1
75th percentile     1
Maximum     5

Specific Weight Adjustment for Number of Eligible Household Members

The probability of selecting an individual respondent depends upon the number of eligible respondents in the household. The table below provides summary statistics for the number of eligible members in the monthly sampled households.

Table 2: Number of Eligible Household Members

  Value
Mean 1.964
Standard deviation 0.953
Minimum     1
25th percentile     1
Median     2
75th percentile     2
Maximum    15

Post-Stratification Weight Adjustments

Adjusting weighted survey counts so that they agree with population counts provided by the Census Bureau can compensate for different response rates by demographic subgroups, increase the precision of survey estimates, and reduce the bias present in the estimates resulting from the inclusion of only telephone households.

The cells, used to construct post-stratification adjustments for this month, together with the number of sample observations and the national population estimates from the Census Bureau are shown in the table below.

Table 3: Post-Stratification Cells

Cell Description Sample Size Population
1 Male - Hispanic (Any Race)    23  10,167,034
2 Male - Non-Hispanic Black    37   9,883,467
3 Male - Age 18 - 24 - Non-Hispanic White    29   8,635,241
4 Male - Age 25 - 34 - Non-Hispanic White    64  11,985,017
5 Male - Age 35 - 44 - Non-Hispanic White    69  15,833,339
6 Male - Age 45 - 54 - Non-Hispanic White    77  14,165,493
7 Male - Age 55 - 64 - Non-Hispanic White    60   9,215,914
8 Male - Age 65 or older - Non-Hispanic White    51  11,755,768
9 Male - Non-Hispanic Other    28   4,146,032
10 Female - Hispanic (Any Race)    50  10,625,145
11 Female - Age 18 - 44 - Non-Hispanic Black    26   7,307,267
12 Female - Age 45 or older - Non-Hispanic Black    30   5,144,462
13 Female - Age 18 - 24 - Non-Hispanic White    30   8,531,226
14 Female - Age 25 - 34 - Non-Hispanic White    73  12,373,489
15 Female - Age 35 - 44 - Non-Hispanic White    99  16,061,583
16 Female - Age 45 - 54 - Non-Hispanic White   108  14,513,973
17 Female - Age 55 - 64 - Non-Hispanic White    47   9,837,412
18 Female - Age 65 or older - Non-Hispanic White    89  15,762,147
19 Female - Non-Hispanic Other    29   4,762,691
N/A Missing Demographic Information    20     N/A    
TOTAL 1,039 200,706,700

Data Collection Schedule

The survey was conducted over a ten-day period, from November 3, 2001 through November 11, 2001. A total of 1,039 interviews were completed during the survey period.

Disposition of Sample Telephone Numbers

The table below presents the distribution of household telephone numbers by disposition categories. The number of household cases in each category was then used to calculate a CASRO response rate of approximately 34.4 percent.

Table 4: Distribution of Household Cases by Disposition

Disposition Category Number of Households
Telephone Numbers Available 7,117
Telephone Numbers Released 4,614
Telephone Numbers Not Dialed   220
Telephone Numbers Dialed 4,394
Out-of-Scope Numbers (Ineligible)   973
BG - Business   260
CF - Computer/Fax   146
DS - Disconnected number   515
NC - Number change    26
NQ - No one 18 years old or older in household     4
UNB - Unavailable before and during study period    22
Scope Undetermined 1,282
NA - No answer   530
BZ - Busy     1
AM - Answering machine   195
CCC - Cannot complete call     0
PM - Privacy manager    43
NQL - Eligibility undetermined because of language problems or deafness    19
RFI - Refused to speak with interviewer (screening incomplete)   148
HRI - Initial Refusal - Requested name be removed from calling list   346
OD - Maximum call attempts reached     0
In-Scope Numbers 2,139
Complete 1,039
Partial Complete    24
CB - Callback   214
CBS - Callback Spanish     9
NAQ - No Answer Qualified   387
BZQ - Busy Qualified     5
AMQ - Answering Machine Qualified   219
LMQ - Left Message Qualified     0
CCQ - Cannot Complete Call Qualified     0
PMQ - Privacy Manager Qualified     0
DL - Deaf/Language    63
RFQ - Respondent refusal     9
UN - Unavailable    66
DR - Respondent deceased prior to completion of interview     2
AC - The area code is changed but not the number     0
HRQ - Qualified Refusal - Requested name be removed from calling list   102
CASRO Response Rate 34.40%