MONTANA AGRICULTURAL STATISTICS 85 



STATISTICAL METHODS 



GENERAL 



The Montana Crop and Livestock Reporting Service has two primary objectives: 



1. To develop accurate, reliable agricultural statistics 



2. To move those statistics to users as rapidly as possible 



Data collection to achieve these objectives, in most cases, involves sample surveys of farmers and ranchers, grain com- 

 panies, feed mills, seed dealers, retail stores, and many other agricultural enterprises. 



From data reported by these many sources, statisticians, using all available statistical tools, generate State totals forming 

 offical USDA estimates. Cooperation of USDA and the Montana Department of Agriculture provides resources for 

 breaking State totals into crop reporting districts and counties. 



Montana agricultural statistics are available in two dimensions — State estimates and county or crop reporting district 

 estimates. 



STATE ESTIMATES 



The U.S. Department of Agriculture is required by law to provide National crop and livestock statistics and statistics 

 for each major producing State. 



For many years and to a considerable extent today, mailed non-probability surveys served as the backbone of data 

 gathering. However, probability sampling, a more sophisticated sampling procedure, is being incorporated as funds and 

 applied technology allow. Some types of probability sampling used in Montana are Area Frame Sampling, List Frame 

 Sampling, and Multiple Frame Sampling. Sampling farm operators in a specifically outlined geographic area is known as 

 Area Frame Sampling, while sampling a list of all known producers of a specific commodity is known as List Frame Sampling. 

 A technique called Multiple Frame Sampling takes advantage of the attributes of both the Area and List samples. Area 

 Frame Sampling is used in Montana for a number of acreage and livestock items and Multiple Frame Sampling is used for 

 estimating the cattle inventory and calf crop. 



The concept of probability sampling is maintained in all three types of sampling. Data collection therefore involves 

 personal enumeration and telephone or personal followup for all non-respondents to mail questionnaires. These 

 probability surveys are expensive on a per sampling unit basis but yield State results that have greater precision and allow 

 measurement of the sampling error. 



The Number 1 grain crop in Montana, wheat, is measured by objective yield procedures. Forecasts before harvest 

 incorporate plant counts, kernel and head counts, and weight. Sample fields are entered with permission of growers, by 

 enumerators in May, June, July, August, and September to take counts and measurements. After harvest, gleaning provides 

 estimated harvesting loss. 



COUNTY ESTIMATES 



Federal funding and regulations support State estimates for specific agricultural items that are important in National 

 totals. When additional items or geographic descriptions within States are needed, local funding is required. To provide 

 estimates by county for example, requires a much larger sample because each county must have enough reports to provide 

 a statistically sound basis for estimates. Without going into details of statistical requirements and concepts, it is sufficient to 

 point out that if reporting units display the same variation within county as they do within the entire State, then a sample 

 will be required in each county nearly as large as the State sample. 



Large mailings are needed to place enough questionnaires in the hands of producers in each county. If response is low 

 in some counties, telephone followup is needed to secure additional reports. Also, information for minor crop acres is 

 secured from informed people in each county — such as county agents, ASCS personnel, etc. County assessments and their 

 change from year to year are a reliable indicator for livestock estimates by counties. 



The Montana Department of Agriculture and Wheat Research and Marketing Committee provide funds for local 

 agricultural data. 



CHECK DATA 



In addition to producer surveys, check data are collected from the marketing channels to verify or supplement the 

 grower survey data. These data become available — usually long after harvest and are used to establish final production and 

 marketing figures. 



The final estimate is arrived at when all grower survey data and marketing data (check data such as: handler or 

 processor receipts, slaughter, and market shipments) have been analyzed. These data then become the statistical history 

 against which current forecasts and estimates are viewed. 



