Using ancillary information to stratify and target young
adults and Hispanics in national ABS samples
J. Michael Dennis, Charles DiSogra, Erlina Hendarwan
AAPOR 2012
Orlando, Florida
© GfK 2012
1
50,000+ members
Probability-based ABS recruitment
Recruitment takes place throughout the year
Representative of U.S. adults
Includes:
Adults with no Internet access (24% of adults)
• KN provides laptop and free ISP
Cell phone only (30% of adults)
Spanish-language
Extensive profile data maintained on each member
• demographics, attitudes, behaviors, health, media usage, etc.
Samples from the panel are assigned to projects
• e-mail invitations and a link to the online survey questionnaire
© GfK 2012
2
2
Mail methodology: materials and schedule
Day 7 Reminder PC
Day 28 NR Letter
Current Resident / Residente Actual
123 Your Street
The City, State 99999
Initial Mailing
© GfK 2012
3
Address-Based Sample (ABS) frame
U.S. Postal Service Computerized Delivery Sequence File (CDSF)
~97% coverage of physical addresses
Frequently updated including status of addresses, such as, seasonal homes,
vacant houses, etc.
Can be matched to available landline telephone numbers
Can be geo-coded
Can attach ancillary information from a variety of sources for purposes of:
• Non-response analyses
• Targeting demographic / geographic mailings
• Sample stratification
© GfK 2012
4
4
Research questions

Will the demographic yields using ancillary information in the sample
design be as good as or better than using traditional Census block
data?

Does the use of ancillary information improve the efficiency of
recruiting the demographic groups of interest?

If using ancillary information turns out to be a good strategy, can it be
leveraged to maximize yields?
© GfK 2012
5
Sample stratification in 2010 and 2011
2010
8 national mailings (~22,000 ea.)
Objective:
Increase Hispanics in a national sample
Method used:
Targeted Census blocks with ABS sample
Criteria:
CBs with 30% or more Hispanic population
Design and sample distribution (vs. Frame):
Stratum 1 Hispanic CBs 41% (vs. 14%)
Stratum 2 Balance of CBs 58% (vs. 86%)
Design Effect: 1.60
© GfK 2012
6
Sample stratification in 2010 and 2011
2010
2011
8 national mailings (~22,000 ea.)
8 national mailings (~26,000 ea.)
Objective:
Objective:
Increase Hispanics in a national sample
Increase Hispanics
Increase Young Adults (ages 18-24)
Method used:
Method used:
Targeted Census blocks with ABS sample
Ancillary information with ABS sample
Criteria:
Criteria:
CBs with 30% or more Hispanic population
Hispanic surname for household
Any 18-24 in household and rents home
Design and sample distribution (vs. Frame):
Design and sample distribution (vs. Frame):
Stratum 1 Hispanic CBs 41% (vs. 14%)
Stratum 2 Balance of CBs 58% (vs. 86%)
Stratum 1 Hispanic 18-24 1% (vs. 0.3%)
Stratum 2 Hispanic 25+ 25% (vs. 8%)
Stratum 3 All Else 18-24 7% (vs. 2%)
Stratum 4 All Else 25+
67% (vs. 89%)
Design Effect: 1.60
Design Effect: 1.52
Conservative oversamples (approx. 3x)
© GfK 2012
7
Percent Raw Yield
Raw yield = number of HHs recruited / total HHs in sample
Slightly LOWER yield with ancillary info design
2010
Census Blocks
2011
Ancillary Info.
9.9
9.2
Reason: A function of HISPANIC ancillary info targeting
2010 Census Blocks
Hispanic Else
stratum stratum
18+
18+
9.2
10.4
2011 Ancillary Info.
Hispanic Hispanic Else
Else
stratum stratum stratum stratum
18-24
25+
18-24
25+
8.7
7.7
12.2
9.5
LOWER
© GfK 2012
8
Percent Raw Yield of Hispanics
Raw yield = number of Hispanic HHs recruited / total HHs in sample
NO DIFFERENCE in yield with ancillary info design
2010
Census Blocks
2011
Ancillary Info.
1.8
1.8
A HIGHER Hispanic yield with ancillary info targeting
2010 Census Blocks
Hispanic Else
stratum stratum
18+
18+
3.6
0.6
2011 Ancillary Info.
Hispanic Hispanic Else
Else
stratum stratum stratum stratum
18-24
25+
18-24
25+
6.9
5.7
0.6
0.4
HIGHER
© GfK 2012
9
Percent Raw Yield of Young Adults
Raw yield = number of YA HHs recruited / total HHs in sample
NO DIFFERENCE in yield with ancillary info design
2010
Census Blocks
2011
Ancillary Info.
0.8
0.8
A HIGHER 18-24 AGE GROUP yield with ancillary info targeting
2010 Census Blocks
Hispanic Else
stratum stratum
18+
18+
1.0
0.7
2011 Ancillary Info.
Hispanic Hispanic Else
Else
stratum stratum stratum stratum
18-24
25+
18-24
25+
2.5
0.8
2.6
0.6
HIGHER
© GfK 2012
10
Percent Race/Ethnicity of Recruited
HIGHER EFFICIENCY to locate Hispanics with ancillary info targeting
2010 Census Blocks
Hispanic
Else
stratum stratum
18+
18+
2011 Ancillary Info.
Hispanic Hispanic
Else
Else
stratum stratum stratum stratum
18-24
25+
18-24
25+
Hispanic
39.5
5.5
79.1
73.4
4.6
4.7
African American
15.1
14.4
3.6
3.1
23.0
15.9
Other/2+ race
7.6
5.8
3.2
4.1
6.3
5.9
White
38.7
75.1
14.6
19.6
67.4
74.5
Total *
100.0
100.0
100.0
100.0
100.0
100.0
* May not add to 100% due to rounding.
© GfK 2012
11
Percent Young Adults (18-24) of Recruited
HIGHER EFFICIENCY to locate young adults with ancillary info targeting
2010 Census Blocks
Hispanic
Else
stratum stratum
18+
18+
2011 Ancillary Info.
Hispanic Hispanic
Else
Else
stratum stratum stratum stratum
18-24
25+
18-24
25+
18-24
10.7
7.0
28.6
10.7
21.6
6.2
25-34
22.1
16.2
15.9
25.3
10.3
17.4
35-54
43.1
43.6
44.6
47.5
44.9
40.4
55-64
14.5
18.8
9.6
11.1
16.1
20.1
65+
9.7
14.5
1.4
5.5
7.2
15.8
Total *
100.0
100.0
100.0
100.0
100.0
100.0
* May not add to 100% due to rounding.
© GfK 2012
12
Conclusions

The yields for Hispanics and young adults, using ancillary information
in the sample design, is as good as traditional Census block data
with our 2010 design

The use of ancillary information improved the efficiency of recruiting
Hispanics and young adults (ages 18-24)


© GfK 2012
Improved efficiency was also reflected in a modest 1.7% lower cost per recruited
young adult and 3.2% lower cost per recruited Hispanic in 2011 compared to 2010
Using ancillary information, with more aggressive over-sampling to
take advantage of the higher efficiency, can be leveraged to
maximize yields in future samples
13
Thank you!
J. Michael Dennis
mike.dennis@gfk.com
© GfK 2012
14