2014–15 MacroMonitor Survey Weighting Procedures

Questionnaire Design

The MacroMonitor target for weighting to the national household population in the United States is economic-household units—a definition that allows households to have more than one economic unit. The US Bureau of the Census defines households as persons sharing a common dwelling unit. The MacroMonitor definition of economic household includes families, individuals living alone, and two or more adults living together in a common dwelling who share basic finances. Thus, adults who live together but are unrelated and unmarried—such as housemates, roomers, a cohabiting couple, resident employees, or adult children or other relatives who might contribute to the housing expenses but otherwise maintain separate finances—count as separate economic households.

The KnowledgePanel sample design began as an equal-probability sample, incorporating several enhancements to improve efficiency. Because any alteration in the selection process is a deviation from a pure equal-probability sample design, statistical weighting adjustments to the data offset known selection deviations. We have incorporated these adjustments in the sample's base weight.

Also, several sources of survey error—such as noncoverage nonresponse because of panel recruitment methods and inevitable panel attrition—are an inherent part of any survey process. We addressed these sources of sampling and nonsampling error by using a panel demographic post-stratification weight.

Last, we constructed a set of study-specific post-stratification weights to adjust for the study's sample design and survey nonresponse. Unless otherwise noted, the 2014–15 MacroMonitor study-specific weights are based on household-level demographic and geographic distributions for the noninstitutionalized civilian population ages 18+ from the Current Population Survey, March 2014 Supplement. Respondents were weighted to the derived benchmark distributions in Table 1.

We calculated comparable distributions using all completed cases from the field data. Because study-sample sizes are typically too small to accommodate a complete cross-tabulation of all the survey benchmark variables, we used an iterative proportional fitting for the poststratification weighting adjustment. This procedure adjusts the sample data to the selected benchmark proportions. The weighted sample data optimally fitted to the marginal distributions through an iterative convergence process.

After this poststratification adjustment, we examined the distribution of the weights to identify and, if necessary, trim outliers at the extreme upper tail of the weight distribution. Extremely large weights, though they help the fit of the total sample to the Census marginals, are statistically very unreliable. And because demographically the underrepresented (and overweighted) persons in the sample are typically the young, the low income, and the poorly educated, large weights also increase the relative importance of questionnaire responses of low validity. For these reasons, we capped the largest weights by winsorizing the distribution: We replaced the top 2.5% of weights by the mean value of the top 2.5% of weights. After winsorizing, the range of weights was 0.0716 to 5.5345. We then scaled the poststratified and trimmed weights to the size of the population of economic households in the United States. The final weights ranged from 2.1679 to 167.6596 (ratio 77.3) and summed to 133,443 (000) economic households.

Weighting Targets
2014–15 MacroMonitor

Number of responding households 4,405
Estimated number of household economic units 133,443,000
Household Characteristics Percentage of All US Households
Household Status  
Family 65.9
Nonfamily, single 27.7
Nonfamily, more than one member1 6.4
Total 100%
Census Region  
New England 4.7
Mid-Atlantic 13.3
East-North Central 15.3
West-North Central 6.9
South Atlantic 19.9
East-South Central 6.3
West-South Central 11.6
Mountain 7.2
Pacific 14.9
Total 100%
Metropolitan Area  
Non-Metro 16.2
Metro 83.8
Total 100%
Household Income  
Less than $10 000 7.3
$10 000 to $19 999 11.4
$20 000 to $29 999 10.5
$30 000 to $49 999 18.8
$50 000 to $74 999 17.6
$75 000 to $99 999 11.9
$100 000 to $149 999 12.4
$150 000 or more 10.1
Total 100%
Home-Ownership Status  
Own 64.8
Rent/other 35.2
Total 100%
Household Size  
1 27.7
2 34.1
3 15.7
4 or more 22.5
Total 100%
Presence of Children  
No children younger than age 18 68.5
Children younger than age 18 31.5
Total 100%
Age of Head of Household  
18 to 34 years 21.2
35 to 44 years 17.1
45 to 54 years 19.4
55 to 64 years 18.8
65 years or older 23.5
Total 100%
Ethnicity of Head of Household  
White 68.1
Black or African American 12.4
Hispanic 12.8
Asian Indian 1.0
Other or more than one 5.8
Total 100%
Education of Head of Household  
Grade 0 to 8 4.0
Some high school 6.8
High-school graduate 28.2
Some college 29.0
Bachelor's degree 20.3
Beyond Bachelor's degree 11.7
Total 100%
Internet Access2  
No 25.3
Yes 74.7
Total 100%
Cell-Phone-Only Household3  
No 59.0
Yes 41.0
Total 100%

1 A nonfamily household consists of a one-person household (a householder living alone) or a household in which the householder shares the home exclusively with people to whom he or she is not related.

2 The source of this benchmark is the CPS, October 2012 supplement.

3 The source of this benchmark is the July–December 2013 NHIS.