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Omnibus Survey Household Survey Results Month Specific Information February 2002

Omnibus Survey
Household Survey Results
Month Specific Information
February 2002

This report presents the results of the February 2002 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 February 2002 survey collected data between February 2, 2002 and February 11, 2002. Data were collected from households in the U.S. using a Random-Digit-Dialed telephone methodology. The final completed sample size is 1,053 cases, and the total number of variables in the public-use dataset is 172. 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 February 2002 survey. A total of 6,926 of these numbers were identified as working residential numbers and were divided into 69,69 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. Thirty (30) (includes the 4 replicates used for the pretest) of the 69,69 replicates were not utilized in the actual interviewing, resulting in 3,569 numbers being released for use by the telephone interviewers.

For this survey, the total number of telephone numbers in the sampling frame, N, is 262,863,400. The total number of telephone numbers in the sample (numbers dialed) is 3,569.

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 1.181
Standard deviation 0.497
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 1.967
Standard deviation 0.831
Minimum     1
25th percentile     1
Median     2
75th percentile     2
Maximum     8

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)    40  10,167,034
2 Male - Non-Hispanic Black    37   9,883,467
3 Male - Age 18 - 24 - Non-Hispanic White    22   8,635,241
4 Male - Age 25 - 34 - Non-Hispanic White    47  11,985,017
5 Male - Age 35 - 44 - Non-Hispanic White   101  15,833,339
6 Male - Age 45 - 54 - Non-Hispanic White    88  14,165,493
7 Male - Age 55 - 64 - Non-Hispanic White    49   9,215,914
8 Male - Age 65 or older - Non-Hispanic White    54  11,755,768
9 Male - Non-Hispanic Other    41   4,146,032
10 Female - Hispanic (Any Race)    38  10,625,145
11 Female - Age 18 - 44 - Non-Hispanic Black    29   7,307,267
12 Female - Age 45 or older - Non-Hispanic Black    24   5,144,462
13 Female - Age 18 - 24 - Non-Hispanic White    24   8,531,226
14 Female - Age 25 - 34 - Non-Hispanic White    57  12,373,489
15 Female - Age 35 - 44 - Non-Hispanic White    97  16,061,583
16 Female - Age 45 - 54 - Non-Hispanic White    93  14,513,973
17 Female - Age 55 - 64 - Non-Hispanic White    67   9,837,412
18 Female - Age 65 or older - Non-Hispanic White    84  15,762,147
19 Female - Non-Hispanic Other    34   4,762,691
N/A Missing Demographic Information    27     N/A    
TOTAL 1,053 200,706,700

Data Collection Schedule

The survey was conducted over a ten-day period, from February 2, 2002 through February 11, 2002. A total of 1,053 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 41.5 percent.

Table 4: Distribution of Household Cases by Disposition

Disposition Category Number of Households
Telephone Numbers Available 6,620
Telephone Numbers Released 3,569
Telephone Numbers Not Dialed     0
Telephone Numbers Dialed 3,569
Out-of-Scope Numbers (Ineligible)   788
BG - Business   203
CF - Computer/Fax   138
DS - Disconnected number   397
NC - Number change    21
NQ - No one 18 years old or older in household    13
UNB - Unavailable before and during study period    16
Scope Undetermined  847
NA - No answer   372
BZ - Busy     0
AM - Answering machine   130
LM - Left message     4
CCC - Cannot complete call     2
PM - Privacy manager    28
NQL - Eligibility undetermined because of language problems or deafness    21
RFI - Refused to speak with interviewer (screening incomplete)    57
HRI - Initial Refusal - Requested name be removed from calling list   233
OD - Maximum call attempts reached     0
In-Scope Numbers 1,934
Complete 1,053
Partial Complete    11
CB - Callback   192
CBS - Callback Spanish     0
NAQ - No Answer Qualified   318
BZQ - Busy Qualified     0
AMQ - Answering Machine Qualified   201
LMQ - Left Message Qualified    16
CCQ - Cannot Complete Call Qualified     1
PMQ - Privacy Manager Qualified     6
DL - Deaf/Language    49
RFQ - Respondent refusal     3
UN - Unavailable    60
DR - Respondent deceased prior to completion of interview     0
AC - The area code is changed but not the number     0
HRQ - Qualified Refusal - Requested name be removed from calling list    24
CASRO Response Rate 41.53%