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The Impact of Record Use in the CE 

Interview Survey

Taylor J. Wilson

Economist

Division of Consumer Expenditure Surveys

CE Survey Methods Symposium

18 July 2017
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Roadmap

1. Research Question

2. Materials and Methods

 Identifying Rounded Values

 Order of Magnitude Effects

 Records

3. Results

4. Conclusions
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Research Question

Does the use of records reduce the prevalence of 

rounding in survey responses significantly?

 There are several challenges with answering a 

question like this one.

What does “rounded response” mean and how to 

identify them?

Measuring significance in right skewed 

expenditure distributions. 

Record use questions in the survey.
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Identifying Rounded Values

 Notice that most expenditure frequency 

distributions are “spikey.”

 Coarse data are a red flag for rounded data.

 “Heaping” can be observed in most 

expenditure distributions and is an example of 

data coarseness. 
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Average “Fall” Approach

0

2

4

6

8

10

12

14

16

1 2 3 4 5 6 7 8 9 10 11

Frequency

Expenditure ($)

8

2

12
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Testing Significance

 The distance distributions constructed from 

the falls are generally non-normal right 

skewed. 

 68-95-99 Rule fails to provide accurate 

measure of significance. 

 Chebyshev’s Inequality as a benchmark for 

significance. 

Pr(|X − μ| ≥ kσ) ≤

1

k

2
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Defining the Rounded Value

 A heaped value has the highest probability of 

being a rounded value. 

 Heaped values can be identified as being 

those expenditure frequency values that are 

more than two standard deviations from the 

average fall in a given distribution. 

 Order of magnitude matters, so we restrict the 

domain of evaluation on the orders of 

magnitude. 
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Record Use

 A household is said to have “used records” 

when the field representative notes that the 

household used records greater than 50% of 

the time. 

 Natural Error and Variance in response. 

 Hypothesis is that more record use implies 

less heaping. 
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Record Use

 About half of households have data for record 

use with a small variance depending on the 

selected time frame for analysis. 

 Of those who had data collected, about a 

fourth of these households used records over 

half the time (defined as a record user)

 Independent Variable of Interest
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Record Use Hypothesis

 Heaping is a function of both record use and 

natural prices. 

 When natural prices align with typically 

heaped values, record use does not diminish 

the incidence of heaping. 

 Use different expenditure categories to test 

the hypothesis that record users round less 

than non-record users. 
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Rounding Behavior

 Rounding behavior is not correlated with based on 

CE data:

 Age

 Sex

 Education

 Race

 Correlation matrix reveals absolute correlations at 

all less than 3%.

 Unsurprisingly, the Logistic Regression showed that 

none of the demographics significantly predicted 

roundedness. 
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Mann-Whitney U Test

 Non-parametric test for record use because of 

the non-normal underlying distributions. 

 Allows us to test the hypothesis that the 

probabilities of randomly selecting a value 

from two independent non-normal 

distributions are equal.

 Rank-Sum procedure on two expenditure 

types on a fixed order of magnitude value 

domain. 
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Mann-Whitney U Test

 Record use appears to be generally useful for 

smaller, large price-variance goods and 

services that aren’t purchased on a repeatable 

basis. 

 The following expenditure types were selected 

to exemplify the general behavior and to 

present this juxtaposition. 

Clothing and Accessories 

Subscriptions 
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Clothing and Accessories on Value Domain [0,99]

Two-sample Mann-Whitney U test

records | obs rank sum expected

-------------+---------------------------------------

0 | 291 60178 58345.5

1 | 109 20022 21854.5

-------------+---------------------------------------

combined | 400 80200 80200

H0: Pr(rounded value(records=0)) = Pr(rounded value(records=1))

z = 2.512

P value = 0.0120

The use of records dramatically decreased incidence of 

identified rounded values. Natural prices do not typically fall on 

highly divisible values in this expenditure category so the 

effect of records is expected to be greater. 
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Subscriptions on Value Domain [0,99]

Two-sample Mann-Whitney U test

records | obs rank sum expected

-------------+---------------------------------------

0 | 542 195798.5 195662

1 | 179 64482.5 64619

-------------+---------------------------------------

combined | 721 260281 260281 

H0: Pr(rounded value(records=0)) = Pr(rounded value(records=1))

z = 0.110

P value = 0.9123

The use of records did not decrease incidence of identified 

rounded values. Natural prices typically fall on highly divisible 

values in this expenditure category so the use of records is 

expected to be ineffectual. 
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15 % of all 

observations
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3 % of all 

observations
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Conclusions

 Record use is helpful in improving data quality by 

reducing the coarseness of data for certain 

expenditure types.

 Recommendation is to repeat the analysis for every 

record type on a regular basis to evaluate any 

changes in consumer preferences or natural prices 

that may influence the effectiveness of records in a 

particular expenditure group.

 Spend resources targeting expenditure categories 

with record use incentives where you know record 

use makes a difference. 
Contact Information

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Taylor J. Wilson

Economist

Division of Consumer Expenditure Surveys

www.bls.gov/cex

202-691-6550

wilson.taylor@bls.gov