ITSEW2009 1

REPRESENTATIVE RESPONSE Some Examples

Peter LundquistStatistics Sweden

2

Household Finances 2006 (HF)

Design: Stratified network sample (18 years and older from RTP all household members are included)

Sample size: 17013 households Mode: telephone (approx. 1/2 hour interview)Response rate: 69.6%

Auxiliary variables are matched from external registers

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HF: Estimated Mean Income Divided by Consumption Units

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20165000

170000

175000

180000

185000

190000

195000

WD-event

95% upper limit

Estimate sample

Estimate responding units

95% lower limit

From Westling (2008)

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HF: Comparison Between HT and GREG-estimators

0

10

20

30

40

50

60

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

WD-events

%

Employed HT-estimator

Employed GREG-estimator

Not in labour force HT-estimator

Not in labour force GREG-estimator

From Westling (2008)

5

Living Condition Survey 2007 (LCS)Design: srs, 16 years and older from RTP Sample size: 7694 Mode: telephone (approx. 1 hour interview)Response rate: 73.4%

Auxiliariy variables are matched from external registers

Missing telephone-number for 3.7% of the sample

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LCS: Response Rate

Outcome Rate No. in Sample

%

Respondents 5651 73.4

Noncontacts 664 8.6

Refusals 1194 15.5

Other nonresponse 185 2.4

All 7694 100.0

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LCS: Auxiliary Variables

Age Gender Country of Birth Marital Status Employment status Region Social allowance Type of housing estate Income Education Telephone (Sample based)

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LCS: Major Reasons for Nonresponse Age [Refusal: 35-64 years, Noncont: -34 years, Other:74+ years] Gender Country of Birth [Noncont and Other: born outside Sweden] Marital Status [Noncont: unmarried ] Employment status [Other: unemployed] Region [Noncont: living in big cities] Social allowance [Noncont and Other: if having allowance] Type of housing estate [Noncont: rented housing] Income [Noncont: no income Other: low income] Education [Nocont and Other: education code is missing] Telephone (Sample based) [Noncont: no phone]

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LCS: Logit Model Response as Dependent Parameter Estimates Before and After Nonresponse Follow-up

Resp5w PCT100

Parameter

Estimate Std. Error sign Estimate Std. Error sign

Intercept -0.7815 0.1267 *** -0.5269 0.1315 *** AGE_24 0.7416 0.1002 *** 0.8342 0.1088 *** AGE35_64 -0.0050 0.0760 -0.0466 0.0813 AGE65_74 0.3254 0.1113 *** 0.3102 0.1201 *** AGE75_ 0.3423 0.1237 *** 0.2417 0.1309 * Sw.born 0.1450 0.0730 ** 0.1471 0.0771 * Female 0.1962 0.0510 *** 0.2488 0.0549 *** Employed 0.0967 0.0727 0.1908 0.0782 ** Married 0.2500 0.0571 *** 0.2558 0.0615 *** Big City -0.1367 0.0540 ** -0.2374 0.0576 *** Soc. Allowance -0.3381 0.1553 ** -0.2342 0.1588 Owned housing 0.1383 0.0587 ** 0.1633 0.0634 *** No income -0.2147 0.1099 * -0.2527 0.1151 ** High income 0.2050 0.0666 *** 0.1542 0.0719 ** No edu. code -0.3985 0.2310 * -0.5524 0.2353 ** Low edu. -0.1311 0.0683 * -0.1691 0.0729 ** High edu. 0.3443 0.0777 *** 0.3878 0.0859 *** Telephone 0.9154 0.0829 *** 1.0337 0.0837 ***

*) sign. level 10% **) sign. level 5% ***) sign. level 1%

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LCS: Indicators

Based on estimated response probabilities under srs the following R-indicator (Schouten and Cobben 2007, 2008) is used

s ks n

R 2)ˆˆ(1

121ˆ

and under srs the q2-indicator (Särndal and Lundström 2008) is

krTkk

Ts kk

s kI mmn

mm

q xxxx 122 )()(where)/(ˆ

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LCS: Indicators

A measure of the estimated relative bias (in per cent) is computed by

1100)(

s

EXPEXP y

yyRB

As variables yk Sickness and activity allowance (yes/no), Income, Sickness pay (yes/no) and Employed (yes/no) are used to estimate the relative bias.

All indicators computed for Resp5w and PCT100

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LCS: R and q2 Indicators for Response Before and After Follow-up

)( EXPyRB

Response sR̂ 2ˆ Iq Sick allow. Sick pay Employed Income

Resp5w 0.78 0.089 -8.0 -0.7 3.0 1.6 Refusal 1.8 8.0 1.2 1.5

Noncont+Other 17.2 0.8 -6.6 -3.6 PCT100 0.77 0.062 -8.5 0.7 3.4 1.2

Refusal 4.7 5.2 5.2 6.6 Noncont+Other 50.0 -11.6 -30.1 -16.8

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LCS: Conclusions

The representativity doesn’t increase with the follow-up

The indicators are estimates e.g. they are subject to variation (not computed)

The same goes for the relative bias Active work with strategies for the group having

social allowance and those with missing telephone

Found auxiliary variables could be used in the creation of a new estimator

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Labour Force Survey (LFS) Data from March-December 2007

Annual salary 2006 according to the Swedish Tax Register

Process data from WinDati (CATI-system).

Supplemented with:

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Response Rates for the Reference Weeks in a LFS Month (Means Based on LFS March-December 2007)

.

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

0 5 10 15 20 25 30 35 40 45 50

Response Rate

Field Days

Mresp W1

Mresp W2

Mresp W3

Mresp W4

Mresp W5

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Contact Days for the Reference Weeks in a LFS Month (Means Based on LFS March-December 2007)

0

0,5

1

1,5

2

2,5

3

3,5

0 5 10 15 20 25 30 35 40 45 50

Mean Contact Days

Field day

MV Week1

MV Week2

MV Week3

MV Week4

MV Week5

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Total Number Contact Days, Reference Weeks, in a LFS Month (Means Based on LFS March-December 2007)

0,000

0,100

0,200

0,300

0,400

0,500

0,600

0,700

0,800

0,900

0 2000 4000 6000 8000 10000 12000 14000

Response Rate

Contact Days

Mresp W1

Mresp W2

Mresp W3

Mresp W4

Mresp W5

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Relative Bias for Income Accumulated on Contact Days, in a LFS Month (Means Based on LFS March-December 2007)

-1

0

1

2

3

4

5

6

0 2 4 6 8 10 12 14 16

Relative Bias

Contact Days

Rbias Week1

Rbias Week2

Rbias Week3

Rbias Week4

Rbias Week5

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LFS: Final Variability in Relative Bias for Income, Reference Weeks (Means Based on LFS March-December 2007)

Number of Observations

Mean Relative Bias in Percent

Low 95-Percent confidence interval

High 95-Percent confidence interval

Week 1 10 4.17 3.75 4.58

Week 2 10 3.90 3.46 4.35

Week 3 10 4.22 3.59 4.84

Week 4 10 3.65 3.00 4.29

Week 5 3 4.91 4.33 5.48

All 10 4.08 3.69 4.46

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HF 2006, LCS 2007 and LFS 2007: Estimated Relative Bias of mean Income in SEK in Percent and Outcome Rates

HF 2006 LCS 2007 LFS 2007

Outcome Rate % Rel. Bias

% of Sample*

% Rel. Bias

% of Sample

% Rel. Bias

% of Sample**

Respondents 2.7 70.3 1.2 73.4 4.1 81.7

Refusals 5.1 16.8 6.6 15.5 -1.9 7.8

Noncontacts + Other Nonresp.

-19.8 12.9 -16.8 11.0 -32.8 10.5

*) Based on 36,864 individuals **) Based on the average of 10 months LFS (21,500 individual each month)

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ReferencesCobben, F. and Schouten, B. (2008). An empirical validation of R-indicators. Discussion paper 08006, CBS, Voorburg.

Schouten, B. and Cobben, F. (2007). R-indexes for the comparison of different fieldwork strategies and data collection modes. Discussion paper 07002, CBS, Voorburg.

Särndal, C.E. and Lundström, S. (2008). Assessing auxiliary vectors for control of nonresponse bias in the calibration estimator. Journal of Official Statistics, 24, 167-191.

Westling, S. (2008). “Utveckling för system av kontaktstrategier i intervjuundersökningar med individer och hushåll” Delrapport II, unpublished report, Örebro, Sweden: Statistics Sweden. [In Swedish]