NEW - Feral Swine Surveys - SSB - Apr 2015

Supporting Statement – Part B

FERAL SWINE SURVEY

OMB No. 0535-NEW

B. COLLECTION OF INFORMATION EMPLOYING STATISTICAL METHODS

1. Describe (including a numerical estimate) the potential respondent universe and any sampling or other respondent selection method to be used. Data on the number of entities (e.g., establishments, State and local government units, households, or persons) in the universe covered by the collection and in the corresponding sample are to be provided in tabular form for the universe as a whole and for each of the strata in the proposed sample. Indicate expected response rates for the collection as a whole. If the collection has been conducted previously, include the actual response rate achieved during the last collection.

This benchmark survey will be conducted in 2015 in the 11 States (Alabama, Arkansas, California, Florida, Georgia, Louisiana, North Carolina, Mississippi, Missouri, South Carolina, and Texas) that have high feral swine densities and a significant presence of corn, soybeans, wheat, rice, peanuts and sorghum (Texas). The NASS List Frame will be used to draw a sample of farm operators who produce one or more of the targeted crops (a population of approximately 73,000). The targeted sample will be representative of the farm population in these 11 States.

Control data were used in a simulation to derive means and standard deviation parameters to estimate the sample size for the Feral Pig Survey.  The stratum level sample size formula is:

Where:

h is the stratum,

n is the sample size for stratum h,

N_h is the stratum population,

s_h is the stratum standard deviation,

f_h is the stratum coefficient of variation, and

T_h is the stratum total.

The sample size estimate, using a coefficient of variation value of nine percent, was adjusted upward by an adjustment value (~80%) based on NASS’s historic response rate.  The resulting sample size was rounded to 10,800.     

2. Describe the procedures for the collection of information including:

• statistical methodology for stratification and sample selection,

• estimation procedure,

• degree of accuracy needed for the purpose described in the justification,

• unusual problems requiring specialized sampling procedures

Questionnaires will be mailed around the 16th of June, 2015. Operations that do not respond by mail or internet within a couple of weeks will be attempted by phone or personal enumeration. Responses will be monitored to make sure that the respondents are representative of the stratified sample. Extra efforts will be taken to collect data from any stratum that has insufficient coverage. After data collection is complete, the data will be edited for reasonableness and completeness.

3. Describe methods to maximize response rates and to deal with issues of non-response. The accuracy and reliability of information collected must be shown to be adequate for intended uses. For collections based on sampling a special justification must be provided for any collection that will not yield "reliable" data that can be generalized to the universe studied.

The survey will initially be mailed out to the entire sample. Non-respondents will be attempted by phone and there will be limited field enumerations for respondents who have been coordinated with any other surveys NASS will be conducting at that time. NASS will be using National Association of State Departments of Agriculture (NASDA) enumerators who have been working with NASS surveys for many years. Training will be provided by the NASDA supervisors and by our regional Data Collection Centers.

4. Describe any tests of procedures or methods to be undertaken.

NASS plans to do nine or less cognitive interviews prior to the beginning of data collection. With this being a new data collection effort, NASS will do internal testing of the edit and summary programs before any publications will be generated to insure accuracy of data.

5. Provide the name and telephone number of individuals consulted on statistical aspects of the design and the name of the agency unit, contractor(s), or other person(s) who will actually collect and/or analyze the information for the agency.

The sample size for each State is determined by the Sampling and Frame Development Section, Methodology Division; Section Head is Peter Quan, (202)720-5269.

Data collection is carried out by NASS Field Offices; Field Operation’s Director is Kevin Barnes (202) 720-8220.

The NASS Livestock Branch Chief is Dan Kerestes (202) 720-3570.

The NASS Survey Administrative Statistician in Headquarters for the Feral Swine Survey is Dawn Keen (202)690-8804 in the Commodity Survey Section of the Survey Administration Branch, Census and Survey Division; Acting Branch Chief is Marlo Johnson, (202) 720-3570. The Survey Administrator is responsible for coordination of sampling, questionnaires, data collection, training, Interviewers Manual, Survey Administration Manual, data processing, and other Field Office support.

The national summary is the responsibility of the Summary, Estimation and Disclosure Methodology Branch, Methodology Division; Branch Chief is Jeff Bailey (202)720-4008.

April, 2015