Department of the Treasury, the Office of the Fiscal Assistant Secretary
Request for Emergency Processing and Approval
Request for Information on Processing Garnishment Orders
Part B
Describe (including a numerical estimate) the potential respondent universe and any sampling or other respondent selection methods to be used.
Sampling Plan for Collection of Information from Credit Unions Regarding Garnishment Orders
A representative sample of credit unions with assets that do not exceed $50 million will be polled to determine the typical number of garnishment orders served on smaller credit unions. To obtain both qualitative information and to ensure the sample is representative, the credit unions will also be queried to confirm data on the number of active accounts/members, and the proportion of garnishment orders that relate to individuals who do not have accounts at the credit union.
Sampling Frame. The frame from which the sample is to be drawn will be the National Credit Union Administration’s list of the 3,457 active Federal credit unions with total assets that do not exceed $50 million. The list includes the name, address, ZIP code, cycle date, and total reported assets of each institution. It is assumed that the order of credit unions on the list is not cyclic in some way that would bias the sample.
The list will be sorted by total assets and divided into three strata: assets less than $ 2 million, assets at least $2 million but less than $10 million, and assets of at least $10 million, but less than $50 million. These three strata are of 674, 1,250, and 1,533 units respectively.
Sample Method. The sample will be drawn by applying a systematic sample to the entire frame.
A systematic sample of size n is drawn from a population of size N in proportion N/n = k, or a 1/k sample, by taking every k-th element from the sampling frame after choosing a random starting point. The random starting point can be chosen from the numbers 1 through k by using a random number table. In effect, the entire population is divided into k clusters of elements and one of these clusters is chosen at random when the starting point is chosen. For this sample, k = 10 percent sample of the population
A systematic sampling method will automatically draw samples within the strata such that the share of the total sample represented by any stratum will be proportional to its share of the entire population1.
That systematic sampling is a method in which each element of the population has an equal chance of being selected, i.e., it is a simple random sample, even when the sample size is not an integer factor of the population is well-known2. That is, although the simplest case is where kn = N, the method is still valid when N = kn + c > kn where c is less than k.
As necessary, we will reach out to sampled credit unions by phone to ensure the response rate of 80% within the 10% that are sampled.
Sample Representativeness. Although precautions were taken in establishing the sampling frame and the sampling technique to ensure that a sample which reflects the population of all institutions, additional checks will be employed to validate the representativeness of the sample. In particular, two tests will be applied in each stratum.
In the first test, the average value of assets for sample elements will be compared with the average for institutions not included in the sample. The statistical test applied will be a comparison of these two means within each stratum. The null hypothesis should not be rejected in each of the three cases.
In the second test, the geographic scope will be tested. The institutions in the sample and those not in the sample will be classified into the nine Census Bureau divisions3. This will generate a 9 x 2 contingency table to be tested using a χ2 distribution. If the sample reflects the overall population by geography, the null hypothesis will not be rejected.
Data Analysis. For each stratum and for overall, data analysis generally will be to derive estimates of central tendency, such as the mean or median, and measures of the dispersion, such as the variance or deciles, of the questions requiring numeric responses. The study report will estimate mean or median values for the population. There will also be a comparison of the means between strata to identify significant cases where size affects responses.
Describe the procedures for the collection of information.
Treasury is asking credit unions to answer a series of six factual questions about an administrative process through an on-line survey jointly distributed by the Department of the Treasury and the National Credit Union Administration (NCUA). Treasury is using an on-line survey tool, SurveyMonkey, to design and administer the survey. The use of an on-line survey tool will provide for rapid delivery, quick response time, and the ability to track responses.
The key estimate resulting from this collection of information is the annual number of garnishment orders that a credit union receives for verified members of the credit union, which is derived from questions two and three. The degree of accuracy is targeted to be a coefficient of variation of 15% about this key estimate for each stratum. If we fail to achieve a coefficient of variation of 15%, we will with OMB approval increase the sample size.
Treasury plans to distribute the questionnaire via a link in an email. Responses will be tracked using the “collector” feature of the on-line tool. Using the collector feature will allow Treasury to track responses, send emails to additional entities if necessary, and edit email addresses for messages that have been returned. A sample questionnaire is attached.
Describe methods to maximize response rates and to deal with issues of non-response.
In order to ensure the sample size, Treasury is partnering with the National Credit Union Administration to sponsor this on-line survey. The survey consists of six simple, factual questions. There are no sensitive or subjective questions included in the survey. It is our intent to send a letter or email with the questionnaire or possibly shortly prior to the distribution of the questionnaire to the credit unions explaining the purpose of the questionnaire and asking for their participation.
Treasury intends to make two telephone calls to credit unions that have not responded to the survey by the due date. The first call will be made one day after the response deadline. If there is no response to the first telephone follow-up contact, a second call will be made three days later where we will offer to walk the credit union through the survey.
The sampling frame includes two measures that are amenable to comparisons among subsets of the population: the geographic location and the total assets of each institution. These variables will be used in tests similar to those described above in the section on testing the representativeness of the sample. In this case, the focus of the tests will be for non-response bias or other impacts from non-response. The tests will address whether the subset of the sample that does respond is representative of the entire population and whether there are significant differences in known variables between the set of non-respondents and the set of respondents. When numbers permit, the tests will be applied in each stratum.
In the first test, the average value of assets for the responding sample elements will be compared with the average for the entire frame and with the average for the set of non-responding sample elements. The statistical tests applied will compare these means within each stratum. The null hypothesis, at an appropriate significance level allowing for multiple testing, should not be rejected in each case.
In the second test, the geographic scope will be tested. The institutions responding to the survey and the entire sampling frame will be classified into the nine Census Bureau divisions. This will generate a 9 x 2 contingency table to be tested using a χ2 distribution. If the respondents to sample reflect the overall population by geography, the null hypothesis will not be rejected.
Describe any tests of procedures or methods to be undertaken.
To ensure that this collection of information is not burdensome and that the questions are clearly written and will produce accurate and valid results, Treasury asked the NCUA to review the questionnaire. This was done to ensure that the questions being asked will be understood by all potential respondents. The survey consists of six questions related to a specific process currently being performed by credit unions. As mentioned in question two of this document, the key estimate resulting from this collection of information is the annual number of garnishment orders that a credit union receives for verified members of the credit union, which is derived from questions two and three of the survey. Because the questions are factual, it is unlikely that testing will have an impact on the responses provided. Questions four, five and six ask about the administrative processing of the garnishments served on the credit union. The answers to these three questions will be useful, but will not impact the policy decisions being made.
Provide the names and telephone numbers of individuals consulted on statistical aspects of the design and the name of the agency unit, contractor(s), grantee(s), or other person(s) who will actually collect and/or analyze the information for the agency.
Steve Vajs, Office of the Fiscal Assistant Secretary, Treasury 622-1064
1 If the i-th stratum contains Ni elements, the size of the sample taken from the stratum will be ni with Ni/ni ≈ k unless the strata are embedded in the frame in some way that is a factor of k.
2 Cf. Raj, Des, Sampling Theory, (New York, McGraw-Hill, 1968) pp. 43-48.
3 These are listed at http://www.census.gov/geo/www/us_regdiv.pdf
| File Type | application/msword |
| Author | US Department of Treasury |
| Last Modified By | US Department of Treasury |
| File Modified | 2010-08-19 |
| File Created | 2010-08-19 |