Transcript ICES III June 2007 The Redesign of Agriculture Surveys by Laurie Reedman and Claude Poirier.

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
Estimates of agriculture production for crops,
horticulture, livestock and animal products, as
well as revenues and expenses
To conduct the Census of Agriculture (CEAG)
every 5 years
To 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 burden
Individual; 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 undercoverage 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 Canada
4% of field crop area in Manitoba
9% of the field crop area in Atlantic Canada
10% of program payments in Alberta
22% of total farm capital in New Brunswick
30% of sheep in Alberta
35% of beef cattle in Ontario
Nearly 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 adequate
CEAG 2006
Annual 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 population
Expand scope to also represent the small farms
Augment questionnaire to cover more commodities
Increase 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
peas
Unlikely that the FUS questionnaire would
have detailed commodities
Small 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 Atlantic
Decision:
keep small farm threshold at $10K for all surveys
pilot redesign of FUS, to demonstrate its ability to
measure the under coverage
stratum 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 annually
Size classes based on total field crop area
Key crops are barley, corn for grain, oats,
soybeans, winter wheat and hay
Target sample size is 16,000
Crops Survey continued
Allocated sample to the provinces proportional to
the square root of number of farms
Multivariate allocation to strata, using key
variables
Calculated 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 annually
Size classes (counts of animals) within farm type
Key variables are total cattle, beef cows, total
pigs, sows, total sheep, and also milk cows in
some provinces
Target sample size 10,000
Atlantic Survey
Estimates both crops and livestock variables in
Atlantic provinces, 2 surveys annually
Challenge to measure crops and livestock with
one sample, farms tend to be mixed
Size classes within farm type
Key variables are total cattle, total pigs and total
field crops, and potatoes in Prince Edward Island
Target 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 CVs on
variables
other
variables
Crops
Survey
155,000
16,000
1-2%
3-15%
Livestock
Survey
100,000
10,000
1-2%
3-15%
6,000
1,200
1-4%
5-30%
179,000
18,000
1-3%
4-30%
Atlantic
Survey
Financial
Survey
Large or Complex Farms
Group of people dedicated to collecting and
maintaining data pertaining to the biggest and
most influential farms
Manage the response burden
Profiling once each year
Control number of times they are contacted,
carry-forward information for some survey
occasions
Frame Maintenance
Changes in stratification variables
Minimized by having a robust stratification
Births from the Farm Update Survey
Same probability of selection as rest of frame
Updates from Farm Register
Are they independent, is there a risk of bias?
Deaths
Are 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 Reedman
Email / Courriel: [email protected]
Phone number / Téléphone: 613-951-7301