2011 FDIC National Survey of Unbanked and Underaned Households  •  

Appendix E — FDIC Technical Notes
2011 FDIC National Survey of Unbanked and Underaned Households  •  

The data for this report were collected through a Federal 

Deposit Insurance Corporation (FDIC)-sponsored 

Unbanked/Underbanked Supplement to the Current 

Population Survey (CPS) for June 2011. The CPS is a 

monthly survey of about 54,000 interviewed households 

conducted by the US Census Bureau for the Bureau of 

Labor Statistics (BLS). The survey is based on a scientific 

sample that represents the US civilian, non-institutionalized population, aged 15 or older.

The CPS is the primary source of information on the labor 

force characteristics of the US population, including 

employment, unemployment, and earnings statistics. The 

CPS results include a variety of demographic characteristics, such as age, sex, race, marital status, and educational 

attainment. Additional information about the CPS is 

provided in the Census Bureau’s Technical Paper 66, 

Design and Methodology of the CPS, available at 

http://www.census.gov/cps/.

The CPS is a state-based design in that separate samples 

are selected from each state, so that states serve as the 

primary sampling strata. The sample sizes for each state 

are set so that specific precision requirements for estimating unemployment rates will be met.1

 The sample design 

ensures that most of the households in a given state have 

the same probability of being selected, though in general, 

household selection probabilities will vary across states. 

Because the CPS design is state-based, most of the estimates for the Unbanked/Underbanked Supplement should 

be precise at the state level and for some sub-state areas 

(e.g., large metropolitan statistical areas [MSAs]).

Unbanked/Underbanked Supplement 

The Unbanked/Underbanked Supplement was conducted 

in June 2011. This was the second time this survey had 

been conducted. The first Unbanked/Underbanked 

Supplement was conducted in January 2009. The primary 

purpose of the supplement is to estimate the percentage of 

US households that are “unbanked” and “underbanked” 

and to identify the reasons why. The supplement survey 

instrument used in 2011, attached as Appendix G, 

included approximately 40 questions designed to provide 

this information. The 2011 survey instrument is similar to 

the 2009 survey instrument that the FDIC developed with 

the expertise of a national consulting firm, which specializes in public opinion research, as well as input from the 

Census Bureau’s Demographic Surveys Division and BLS. 

The 2009 survey instrument underwent four rounds of 

cognitive field pre-testing and was revised to address the 

1 The precision targets that are the basis for the sample design of the 

CPS are provided on pp.3–1 in Chapter 3 of the US Census Bureau’s 

Technical Paper 66, available at http://www.census.gov/prod/2006pubs/

tp-66.pdf. 

feedback gathered from each round.2 The 2011 survey 

instrument underwent an expert review process by the US 

Census Bureau. For a detailed description of the revisions, 

see Appendix F (Revisions to the 2011 Survey Instrument). Because of changes in the questionnaire, direct 

comparisons between 2009 and 2011 estimates are limited 

and in some instances not possible.

Eligibility and Exclusions

All households that participated in the June 2011 CPS 

were eligible to participate in the Unbanked/Underbanked 

Supplement. However, only households whose respondents specified that they had some level of participation 

in their household finances and also responded “Yes” or 

“No” to whether someone in their household had a bank 

account (survey supplement Question 2, or Q2) were 

considered survey respondents.3 CPS household respondents who did not answer or answered “don’t know” to 

Q2, or who did not participate in their household financial decisions (or refused to answer) were asked no further 

questions and were classified as nonrespondents for the 

supplement. This definition of supplement respondent is 

different from the one used in the 2009 FDIC Survey of 

Unbanked and Underbanked Households report. In 2009, 

a respondent was required only to answer “yes” or “no” to 

whether the households had an account in order to be 

considered a survey respondent. The revised 2009 estimates presented in this report use the 2011 definition of 

respondent so that the estimates are comparable to the 

2011 results. It is worth noting that the revised 2009 estimates are not materially different from those in the 2009 

report.

Demographic characteristics, such as race, age, education, 

and employment, associated with a respondent household 

for the supplement are those reported for the householder/

reference person (i.e., a person who owns or rents the 

home, as designated by the respondent). These demographic characteristics were used in preparing report estimates and tables.

2 The goal of each round was to determine respondents’ comprehension 

of each question, test the flow of the questions, find major recall difficulties, ascertain the sensitivity or inappropriateness of any questions, and 

gauge the operational feasibility of the supplement. No changes to the 

survey were recommended following the fourth round of testing.

3 Respondents involved in their household finances include respondents 

in households where adults have separate finances or in households 

where the respondent was the only adult in the household. For households where adults share finances or have a mix of shared and separate 

finances, respondents were asked to specify how much they participated 

in their household financial decisions. Only those who reported having at 

least some level of participation were considered to be involved in their 

household finances. 
2011 FDIC National Survey of Unbanked and Underaned Households  •  

The weights calculated by the Census Bureau for the CPS 

and the Unbanked/Underbanked Supplement respondents 

were adjusted to account for both nonresponse and undercoverage. These weight adjustments help correct any 

biases in estimates because of nonresponse and undercoverage, so that results from the CPS are “representative” of 

the civilian, non-institutionalized US population, aged 15 

and older.6

Analysis of Supplement Survey Results

Using supplement survey results, households were classified as “unbanked” if they answered “no” to the question, 

“Do you or does anyone in your household currently have 

a checking or savings account?” Households answering 

“yes” to this question were classified as “underbanked” if 

they indicated that they had used at least one of the 

following alternative financial servicea: non-bank money 

orders, non-bank check-cashing services, non-bank remittances, payday loans, rent-to-own services, pawn shops, or 

refund anticipation loans, at least once in the last 12 

months. Note that the 2011 definition of “underbanked” 

has been revised from the 2009 definition to include 

households that used non-bank remittances in the last 

year. The 2011 underbanked definition was also modified 

to include only households that used a refund anticipation 

loan in the last year, as opposed to in the last five years as 

defined in the 2009 report. Consequently, 2011 underbanked estimates are not directly comparable to 2009 estimates (see Box 2 on page 19).

The estimated proportion of US households that are 

unbanked was derived by dividing the sum of the weights 

of the household respondents who were identified as being 

unbanked by the sum of the weights of all household 

respondents. The same formula was used to estimate the 

proportion of US households that are underbanked. For 

estimated proportions of unbanked or underbanked households for demographic subgroups, the same computational 

approach was used and applied to respondent households 

in the subgroup. 

In addition to presenting estimated proportions, many of 

the tables in this report include estimated numbers of 

households (e.g., total households, unbanked households, 

or underbanked households). An estimated number of 

households for a given category (such as unbanked) is 

derived as the sum of the weights of the sample households in that category. For example, for the entire supplement sample of about 44,905 respondent households, the 

sum of the household weights is 120,408,000, which 

6 This adjustment is done by introducing three stages of ratio estimation 

that adjust weights to align with population control totals (independent 

population estimates for various demographic groups). The household 

weight is generally taken to be the weight of the householder/reference 

person. 

Coverage and Response Rates 

The target universe for the CPS is all civilian non-institutionalized persons (aged 15 or older) residing in the 50 

states and the District of Columbia. To reach this 

universe, a list (sampling frame) of about 110 million 

households was developed from the Master Address File 

used for the 2000 Census, plus three additional frame 

sources (group quarters, area canvassing, and building 

permits). 

For the June 2011 CPS, a statistical sample of approximately 58,900 survey-eligible households was selected 

from the sampling frame. Of these, about 53,700 households participated in the CPS, resulting in a 91.2 percent 

response rate. There were about 5,200 nonrespondent 

households. Most of these nonrespondents either refused 

to participate (59 percent of nonrespondents) or were not 

home at the time of the interview visit or call (23 

percent). The remaining 18 percent consisted of households where (a) the household respondent was temporarily 

absent, (b) the household could not be located, (c) 

language barriers prevented the interview, or (d) “other” 

reasons. Because of the availability of translators for many 

languages, only 0.5 percent of the nonrespondents (25 

households) did not participate as a result of language 

barriers. 

About 44,900 (84 percent) of the 53,700 households 

participating in the CPS also participated in the 

Unbanked/Underbanked Supplement.4

 The supplement 

survey response rates vary by demographic groups, ranging 

from 79 percent to 86 percent. 

Coverage ratios for the CPS are derived as a measure of 

the percentage of persons in the target universe (civilian 

non-institutionalized persons aged 15 or older in the 

United States) who are included in the sampling frame.5

The overall coverage ratio for the June 2011 CPS was 87 

percent. The missing 13 percent consists of three groups: 

(1) persons residing in households not in the CPS 

sampling frame, (2) non-institutionalized persons not 

residing in households at the time the CPS was 

conducted, and (3) household residents not listed as 

household members for the CPS for various reasons. The 

coverage ratios varied across demographic groups. For 

example, the coverage ratio was 88 percent for whites, 81 

percent for blacks, and 85 percent for Hispanics. 

4 Taking into account the nonresponse to basic CPS questions, the overall response rate for the Unbanked/Underbanked Supplement was 76 

percent.

5 The coverage ratio is the weighted number of persons in a demographic group (after weights are adjusted to account for household 

nonresponse) divided by an independent count of persons in that demographic group (obtained from the 2000 Census with updates based on the 

American Community Survey). 
2011 FDIC National Survey of Unbanked and Underaned Households  •  

householder cannot be classified into any of the preceding 

groups. 

Data analysts should exercise caution when comparing 

2009 and 2011 estimates by income categories given that 

households with missing information were not treated the 

same way in both data sets. In the 2009 data set, about 15 

percent of households had missing income information 

and were assigned to the “missing” income category. 

However, in the 2011 data set, the US Census Bureau 

imputed income data to households for which this information was missing. Except when making comparisons to 

2009, the 2011 results use imputed income to classify 

household income. When comparing to 2009 results, 2011 

respondent households with missing income are assigned 

to a “missing” income category. 

The counties included in some of the MSAs selected for 

the CPS do not correspond exactly to the counties 

included for these MSAs in the official definitions 

prepared by the Office of Management and Budget 

(OMB) for two reasons. 

First, in redesigning the CPS in a timely manner to incorporate results from the 2000 Decennial Census, the 

Census Bureau had to project revised MSA definitions 

prior to the release of the official OMB definitions in 

2003. Therefore, in some cases, the Census Bureau 

included one or two counties in an MSA for the CPS that 

were not subsequently included in the official definition of 

the MSA. In other cases, the Census Bureau excluded one 

or two counties that were subsequently included in the 

official definitions of an MSA. In the latter case, the data 

for the MSA in the CPS (and in the Unbanked/Underbanked Supplement) will not include any responses for 

one or two of the counties that are a part of the official 

definition of the MSA.7

Second, since the CPS is a state-based design, MSAs that 

include counties in more than one state are subdivided 

into their respective state components for sampling 

purposes. Therefore, for some multi-state MSAs, the counties belonging to one or two of the states were not selected 

for the CPS sample, even though the counties making up 

the other portion of the MSA were selected. The larger 

portions are usually included in the CPS since they would 

be selected with certainty for their state sample because of 

their size (i.e., those larger portions would be “self-representing”). In addition, for some multi-state MSAs, the 

part of the MSA contained in a given state is selected for 

the CPS sample but cannot be identified as belonging to 

the MSA (for confidentiality reasons) because it contains 

fewer than 100,000 people. In such cases, the respondents 

7 In the former case, data for any counties that were not subsequently 

included in the official definition of an MSA are coded as 

non-metropolitan. 

would be an estimate of all US households as of June 

2011. However, the Housing and Vacancy Survey, 

another survey related to the CPS that uses household 

controls to produce household weights, provided an estimate of 112,464,000 as the number of households in June 

2011. This difference (120,408,000 vs. 112,464,000) is 

because household weights prepared by Census for the 

CPS and for this supplement survey are generally taken to 

be the reference person weights and are not adjusted to 

align with household count controls. Household count 

controls were not used to adjust household weights 

because the CPS is a person survey rather than a household survey; therefore, universe controls were used only in 

the preparation of person weights. As a result, the sum of 

household weights shown in our tables for a category tends 

to be higher than the actual household count for the 

category.

This report also contains a number of tables for which 

unbanked percentages and other household statistics are 

computed for subgroups defined by a particular economic 

or demographic characteristic. The household classification of an economic or demographic variable that is 

defined at the person level rather than the household 

level (e.g., race, education, or employment status) is based 

on the economic or demographic classification of the 

householder/reference person (i.e., a person who owns or 

rents the home). 

The Census Bureau classifies households into different 

household types. For instance, a family household is a 

household that includes two or more people related by 

birth, marriage, or adoption and residing together, along 

with any unrelated people who may be residing there. 

Detailed definitions regarding household types can be 

found in the CPS Glossary available at http://www.census.

gov/apsd/techdoc/cps/mar97/glossary.html.

Households are categorized into racial-ethnic classifications as follows: If the householder is identified as black, 

the household is classified as “Black” regardless of whether 

the householder is identified as Hispanic or any other 

race. If the householder is not identified as black and is 

identified as Hispanic, the household is classified as 

“Hispanic Non-Black.” If the householder is identified as 

white and not any other race and non-Hispanic, then the 

household is classified as “White.” All remaining households are classified as “Other.” However, in some national 

summary tables, the “Other” category is further disaggregated into “Asian” if the householder is identified as 

Asian, “American Indian/Alaskan” if the householder is 

identified as American Indian/Alaskan and not Asian, 

and “Hawaiian/Pacific Islander” if the householder is identified as Hawaiian/Pacific Islander and not Asian or 

American Indian/Alaskan. In these tables, “Other” 

consists of the few remaining households in which the 
2011 FDIC National Survey of Unbanked and Underaned Households  •  

in that state usually would be identified as belonging to a 

metropolitan area, but the specific MSA would not be 

identified.

Statistical Precision of Estimates

Standard errors were calculated for certain Unbanked/

Underbanked Supplement Report estimates to indicate 

the precision of these estimates. For example, the standard 

error can be used to compute a 95 percent confidence 

interval for a survey estimate (this is generally computed 

as the estimate plus or minus two times the standard 

error). If the survey estimate of interest is a difference 

between estimates for different groups, the estimated standard error of the difference can be used to determine 

whether the observed difference is “statistically significant.” Differences discussed in this report are significant at 

the 10 percent level of significance. That is, if there was 

no difference in the true universe values of the two sample 

estimates being compared, the probability of obtaining 

sample estimates having this observed difference or a 

larger difference would be no more than 10 percent, and 

could be considerably less.

The standard errors presented in the full report on the 

FDIC’s Unbanked/Underbanked Supplement were calculated based on the variation of a survey estimate across a 

set of 160 sample replicates provided by the Census 

Bureau. Details of the calculation of standard errors based 

on sample replicates (and on the CPS methodology in 

general) are available from the Census Bureau.8

For an estimated difference between a universe quantity 

for the 2009 and 2011 Unbanked/Underbanked surveys 

(such as the difference between the number of unbanked 

households), the derivation of the standard error of such 

an estimated difference was based on the fact that estimates from the 2009 and 2011 surveys are independent. 

Therefore, the standard error of the estimated difference is 

the square root of the sum of the variances of the two 

separate estimates. Sample estimates of these variances, 

based on the use of the set of 160 replicates as described 

above, were used to estimate the standard error of a difference of estimates between the two years. The significance 

of any observed difference between estimates from the two 

years is assessed based on the estimated standard error of 

the difference.

8 For a detailed description of the methodology used to calculate standard errors using replicates, see US Census Bureau Technical Paper No. 

66, Chapter 14, available at http://www.census.gov/prod/2006pubs/tp-66.

pdf.