Appendix A 
Statistical Methodology 
THE CENSUS POPULATION 
The target population for the census of aquaculture 
was composed of all farms that reported any amount 
of aquaculture activity during the 2012 Census of 
Agriculture. An effort was made to identify 
additional aquaculture operations of significance 
from new sources. 
DATA COLLECTION 
Method of Enumeration 
The 2013 Census of Aquaculture was conducted 
primarily by mail. It was supplemented with 
Electronic Data reporting (EDR) via the Internet, 
telephone calls, and personal enumeration. 
Enumeration methods were similar to those used in 
the 2005 Census of Aquaculture. 
Report Forms 
One version of the report form was used in all States. 
A 16-page 2013 Census of Aquaculture report form 
was designed to collect data from operations 
producing or distributing aquaculture. It was 
designed to collect data that also supported the 
agricultural surveys conducted for catfish and trout 
production which are part of the National 
Agricultural Statistics Service’s (NASS) Estimates 
Program. See Appendix B for changes and a copy of 
this report form. 
Report Form Mailings and Respondent 
Follow-up 
The initial mailout took place in December 2013. 
Mail packets were mailed to approximately 4,100 
farms thought to have produced aquaculture in 2012. 
The initial mail packets included a labeled report 
form, an instruction sheet, a letter requesting a 
prompt response and instructions for completing the 
2012 Census of Agriculture 
USDA, National Agricultural Statistics Service 
form via Internet (an alternate reporting option), and 
a postage-paid return envelope. Mailout packet 
preparation, initial mailout, and one follow-up 
mailing to nonrespondents were handled by the 
Census Bureau’s National Processing Center (NPC) 
in Jeffersonville, IN. Telephone follow-ups, 
conducted from a NASS Data Collection Center, 
began in February 2014 to nonrespondents who were 
mailed a report form from NPC. 
Data were collected for a select group of operations 
by the NASS field offices. To minimize the number 
of agency contacts, operations included in this group 
were flagged for contact by NASS for other 
agricultural surveys. Report forms were labeled at 
NPC and sent to field offices in November 2013. 
Field office staff collected data by personal 
enumeration or by phone from December 2013 
through June 2014. For a description of the 
adjustment for nonresponse, see Estimation. 
REPORT FORM PROCESSING 
Data Capture 
All report forms returned to NPC were immediately 
checked in using bar codes printed on the mailing 
label. This check-in process removed the responding 
farms from follow-up mailings. All forms were 
reviewed prior to data keying to identify 
inconsistencies and ensure that the data could be 
keyed. Major inconsistencies, respondent remarks, 
blank report forms, and large aquaculture cases were 
reviewed by analysts and adjusted prior to data 
keying, as needed. All forms with any data were 
scanned and an image was created for each page of a 
report form. 
Data Editing and Anaiysis 
Data from each report form were processed through 
a computer edit which flagged inconsistent entries. 
APPENDIX A A-1 
