ices iii june 2007
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ICES III June 2007. The Redesign of Agriculture Surveys by Laurie Reedman and Claude Poirier. Outline. Background Current Situation Priorities Scope Issues Next Steps. Mandate of the Agriculture Statistics Program. - PowerPoint PPT PresentationTRANSCRIPT
ICES III June 2007
The Redesign of Agriculture Surveys
by
Laurie Reedman and Claude Poirier
Outline
BackgroundCurrent SituationPrioritiesScopeIssuesNext Steps
Mandate of the Agriculture Statistics Program
Estimates of agriculture production for crops, horticulture, livestock and animal products, as well as revenues and expensesTo conduct the Census of Agriculture (CEAG) every 5 yearsTo manage the statistical system of Canada's agriculture sector from data collection to publication Ensure quality outputs for economic analysis and policy making in Canada
Current Situation
Large regular surveys: Crops, Livestock, Hogs, Atlantic, Farm Financial, Fruit and Vegetables, Greenhouse, Sod and Nursery
Smaller regular surveys: Potato Area and Yield, Potato Prices, other prices
Irregular surveys: cost recovery surveys on the environment, farming practices, risk management
Administrative data
Farm Register (FR)
Priorities
Reduce response burdenIndividual; whole population
Improve robustness
Standardize methods and adopt “best practices”
Coverage
Efficient use of internal resources
Efficient use of the farming community’s capacity to respond
Scope
The surveys that use a static frame for the 5 year period between censuses:
Crops
Livestock
Atlantic
Farm Financial
The methodology of survey design
Small Farm Exclusion Threshold
Want to reduce burden on the many small farms that do not have much impact on survey estimates
Propose a method to compensate for the under-coverage that would result from excluding the small farms from the regular survey sampling
Who are the small farms?
Current small farm threshold is $10K reported for the sale of agriculture products on CEAG
21% of all farms and 0.6% of total sales
Other small farm thresholds could be:$25K, 39% of all farms, 2.4% of total sales
$50K, 53% of all farms, 5.6% of total sales
The bottom 5% of sales in each province, 50% of farms
What do the small farms contribute?
Say threshold is $25K in sales on CEAG 2006 …2% of hogs in Canada4% of field crop area in Manitoba9% of the field crop area in Atlantic Canada10% of program payments in Alberta22% of total farm capital in New Brunswick30% of sheep in Alberta35% of beef cattle in OntarioNearly 100,000 acres in different varieties of lentils, beans, dry peas and chick peas in Saskatchewan and Alberta
How to estimate for the small farms if not through regular surveys
Admin sources (tax) do not have commodity data, not adequateCEAG 2006Annual Farm Update Survey (FUS)
Sample is drawn from tax records, producer lists and the margins of the FR to detect farms not already in the active populationExpand scope to also represent the small farmsAugment questionnaire to cover more commoditiesIncrease sample size to provide reliable estimates
Factors in Decision Making
CEAG and/or FUS can adequately estimate livestock variables, the major crops and many components of the Farm Financial Survey (FFS)CEAG questionnaire does not have the varieties of lentils, beans, dry peas and chick peasUnlikely that the FUS questionnaire would have detailed commoditiesSmall farms are part of the target population for some FFS concepts
Decision for 2006 Redesign
Risk of under coverage is too high …Crops and FFS are not ready to raise the small farm exclusion threshold Not feasible to redesign FUS just for Livestock and AtlanticDecision:
keep small farm threshold at $10K for all surveyspilot redesign of FUS, to demonstrate its ability to measure the under coveragestratum boundary at $25K
Stratification and Sample Allocation
Reduce sample sizes, ensure reliable estimates for domains of interest
As few strata as necessary
As few take-all strata as necessary
Use generalized software
Stratify once for the 5 year period
Crops Survey
Estimate acreage of crops, production and yield at provincial as well as sub-provincial level, 6 surveys annuallySize classes based on total field crop areaKey crops are barley, corn for grain, oats, soybeans, winter wheat and hayTarget sample size is 16,000
Crops Survey continued
Allocated sample to the provinces proportional to the square root of number of farmsMultivariate allocation to strata, using key variablesCalculated theoretical coefficients of variation (CVs) and also selected a random sample and verified that there were no deviations in the estimates
Livestock Survey
Estimates totals of different types of cattle, sheep and hogs, at provincial level, 2 surveys annuallySize classes (counts of animals) within farm typeKey variables are total cattle, beef cows, total pigs, sows, total sheep, and also milk cows in some provincesTarget sample size 10,000
Atlantic Survey
Estimates both crops and livestock variables in Atlantic provinces, 2 surveys annuallyChallenge to measure crops and livestock with one sample, farms tend to be mixedSize classes within farm typeKey variables are total cattle, total pigs and total field crops, and potatoes in Prince Edward IslandTarget sample size 1,200
Farm Financial Survey
Estimates financial activity and farm characteristics at provincial level, 1 survey annually
Size classes (total assets) within farm type
Sample is allocated based on total farm revenue
Sample size is usually 18,000
Summary of Sample Allocation
Population Size
Sample Size
CVs on key variables
CVs on other variables
Crops Survey
155,000 16,000 1-2% 3-15%
Livestock Survey
100,000 10,000 1-2% 3-15%
Atlantic
Survey
6,000 1,200 1-4% 5-30%
Financial Survey
179,000 18,000 1-3% 4-30%
Large or Complex Farms
Group of people dedicated to collecting and maintaining data pertaining to the biggest and most influential farmsManage the response burdenProfiling once each yearControl number of times they are contacted, carry-forward information for some survey occasions
Frame Maintenance
Changes in stratification variablesMinimized by having a robust stratification
Births from the Farm Update SurveySame probability of selection as rest of frame
Updates from Farm RegisterAre they independent, is there a risk of bias?
DeathsAre they independent, can we drop them?
Partnerships, buy-outs, splits
Sample Co-ordination
Permanent random numbers
Moving, growing sampling windows
What to do about strata with high sampling fractions
What to do about births
What to do about irregular surveys
What to do about special requests, for example, when more sample is needed to improve precision for a particular domain
Next Steps
Confirm all assumptions and decisions with CEAG 2006 data
Create new survey frames
Select samples
Monitor performance on first few survey occasions, evaluate performance
Estimation system, review of the Farm Register
Redesign FUS
Examine target population definition
Thank-you
For more information, or
to obtain a French copy
of this presentation,
please contact:
Pour de plus amples
informations ou pour obtenir
une copie en français du
document, veuillez
contacter:
Laurie ReedmanEmail / Courriel: [email protected] number / Téléphone: 613-951-7301