Overview of Sample Surveys for Forecasting

1
Overview of Sample Surveys forForecasting
Estimating U.S. Crops

• presented by
• Theresa Terry Holland
• National Agricultural Statistics Service
• U.S. Department of Agriculture
• Regional Workshop on
• Sampling for Agricultural Surveys
• 23 June 2011
• Montevideo, Uruguay

2
NASS Data Series for U.S. Crops

• Crop Progress Condition
• Areaplanted harvested
• Production
• Stocks
• Prices Received by Farmers
• Monthly Marketings
• Values

3
U.S. Crop Standards
standard weight standard moisture standard price marketing yearstarts
Wheat 60 lb (27.2 kg) per bushel 13.5 /bu June 1
Barley 48 lb (21.8 kg) per bushel 14.5 /bu June 1
Oats 32 lb (14.5 kg) per bushel 14.0 /bu June 1
Flaxseed 56 lb (25.4 kg) per bushel 8.0 /bu June 1
Cotton 480 lb (217.4 kg) per bale /lb August 1
Rice 100 lb (45.3 kg) per hundredweight /cwt August 1
Corn 56 lb (25.4 kg) per bushel 15.5 /bu September 1
Sorghum 56 lb (25.4 kg) per bushel 14.0 /cwt September 1
Soybeans 60 lb (27.2 kg) per bushel 14.0 /bu September 1
Sunflowers 100 lb (45.3 kg) per hundredweight 8.0 /cwt September 1
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System of Crop Forecasts Estimates

• early season
• area/trees planted
• area/trees expected for harvest
• during season
• yield forecasts
• end of season
• area/trees harvested
• total production
• end of marketing year
• revised total production

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Possible Methods for Crop Forecasting Estimation

• growers actual data
• area/trees planted/harvested
• quantities harvested/sold/stored
• growers expectations
• areas expected to be planted/harvested
• expected yields
• objective counts measurements
• plant/fruit counts measurements
• expert opinion
• crop progress
• growing conditions
• remote sensing

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NASS Survey Program for Major Crops
jan feb mar apr may jun jul aug sep oct nov dec

Crop Yield Surveys small grains small grains small grains small grains small grains
Crop Yield Surveys summer crops summer crops summer crops summer crops summer crops
Quarterly Agricultural Surveys
summer crops planting intentions planting intentions planting intentions planted area harvest intentions planted area harvest intentions planted area harvest intentions planted area harvested area production planted area harvested area production planted area harvested area production
small grains planted area harvest intentions planted area harvest intentions planted area harvest intentions planted area harvest intentions planted area harvest intentions planted area harvest intentions planted area harvested area production planted area harvested area production planted area harvested area production planted area (for harvest next year) planted area (for harvest next year) planted area (for harvest next year)
on-farm grain stocks storage capacity quantity stored storage capacity quantity stored storage capacity quantity stored storage capacity quantity stored small grains - final old crop storage capacity quantity stored small grains - final old crop storage capacity quantity stored small grains - final old crop storage capacity quantity stored summer crops - final old crop storage capacity quantity stored summer crops - final old crop storage capacity quantity stored summer crops - final old crop storage capacity quantity stored storage capacity quantity stored storage capacity quantity stored

Off-farm Grain Stocks Surveys
Prices Received by Farmers
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Quarterly Agricultural Surveys

• sample
• based on
• total cropland
• areas of specific crops
• grain storage capacity
• data obtained
• areas
• intended vs. actual
• planted vs. harvested
• production
• grain stored on farm
• data collection modes
• mail questionnaireInternet questionnairetelephon
  e/CATI interview
• personal interview

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Crop Acreage, Yield Production
production production production
area x yield
QuarterlyAgriculturalSurveys Agricultural Yield Surveys Objective Yield Surveys
QuarterlyAgriculturalSurveys
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Crop Yield Surveys
Agricultural Yield Objective Yield
samples samples
March June Ag Surveys March June Ag Surveys
crops of interest rotated out reps exclude high strata exclude NOL crops of interest
supplemental
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Crop Yield Surveys
Agricultural Yield Agricultural Yield Objective Yield
commodities surveyed commodities surveyed commodities surveyed
small grains small grains small grains
barley oats winter wheat durum wheat other spring wheat barley oats winter wheat durum wheat other spring wheat winter wheat
summer crops summer crops summer crops
corn cotton dry beans hay peanuts rice tobacco sorghum soybeans sugarcane sunflowers canola corn cotton soybeans potatoes
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Crop Yield Surveys
Agricultural Yield Objective Yield
data obtained data obtained
farmer reported yields yields based onfield counts measurements
area updates area updates
data collection modes data collection modes
mail questionnaireInternet questionnaire telephone/CATI interview personal interview field visit personal interview
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Crop Yield Surveys
Agricultural Yield Objective Yield
advantage advantage
inexpensive objective
disadvantage disadvantage
subjective expensive
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Crop Yield Surveys

• small grains May thru September
• summer crops August thru November

data collection starts25th of previous month
yields to reflect conditions as of 1st of month
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Objective Yield Sample Sizes
number ofStates ofU.S. crop samplesize
Wheat 10 53 1410
Corn 10 84 1920
Soybeans 11 84 1835
Cotton 6 75 1227
Potatoes 7 75 1290
updated 2010
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Objective Yield Sample Sizes

• WHEAT n1410
• 10 states average 67 of U.S. winter wheat
  production
• winter wheat in the 10 states averages 50 of
  U.S. production of all wheat

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Objective Yield Sample Sizes

• CORN n1920
• 10 states average 84 of U.S. corn production

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Objective Yield Sample Sizes

• SOYBEANS n1835
• 11 states average 84 of U.S. soybean production

18
Objective Yield Sample Sizes

• COTTON n1227
• 6 states average 75 of U.S. upland cotton
  production
• upland cotton in the 6 states averages 65 of
  U.S. production of all cotton

19
Objective Yield Sample Sizes

• POTATOES n1290
• 7 states average 83 of U.S. fall potato
  production
• fall potatoes in the 7 states average 75 of U.S.
  production of all potatoes

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Objective Yield Sampling
Fields are selected based on area expected for
harvest.
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Objective Yield Sampling
segment tract field crop acres expansion factor expanded crop acres cumulativeexpanded crop acres selected acres selected acres
4087 6 1 130.0 53.000 6890.00 6890.00 1306.11
5030 1 2 69.0 53.000 3657.00 10547.00 10269.71
5030 1 5 59.0 53.000 3127.00 139674.00
6049 3 2 17.0 53.000 901.00 14575.00
6049 3 4 62.0 53.000 3286.00 17861.00
5031 2 2 33.0 53.000 1749.00 19610.00 19233.31
6145 2 3 34.0 53.000 1802.00 21412.00
6145 2 5 48.5 53.000 2570.50 23982.50
4381 1 2 65.0 194.000 12610.00 36592.50 21896.91
5391 1 3 78.0 194.000 15132.00 51724.50 37160.51 46124.11
4476 4 1 105.0 106.143 11145.01 62869.51 55087.71
4485 1 2 80.0 106.143 8491.44 71360.95 64051.31
4485 1 4 100.0 106.143 10614.30 81975.25 73014.91
4494 5 1 87.0 106.143 9234.44 91209.69 81978.51 90942.11
4494 5 2 48.0 106.143 5094.86 96304.55
4494 5 3 85.0 106.143 9022.15 105326.70 99905.71
4494 5 4 100.0 106.143 10614.30 115941.00 108869.31
6467 1 4 32.0 106.143 3396.58 119337.58 117832.91
? ? ? ? ? ?
4153 1 6 9.0 53.000 477.00 895617.99
4153 1 7 14.0 53.000 742.00 896359.99

• interval total expanded acres/sample size
  896359.99/100 8963.60
• random start ? (0. interval 1306.11

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Objective Yield Sampling

• Samples consist of 2 plotsrandomly located
  within each selected field.

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Objective Yield Sampling

• Each plot consists of a 5-foot buffer a count
  area.

count area count area count area
Wheat 3 rows x 21.6 inches
Corn 2 rows x 15 feet
Cotton 2 rows x 10 feet
Soybeans 2 rows x 3.5 feet
Potatoes 1 row x 20 feet
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Yield Components
number of fruitper acre x weightper fruit harvest lossper acre
gross yield gross yield gross yield
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Gross Yield Components

• WHEAT

heads per acre grain weight per head
at harvest heads grain weightmoisture content
forecast stalksheads in bootemerged heads historical averagefertile spikeletsgrains per headhead weight
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Gross Yield Components

• CORN

ears per acre grain weight per ear
at harvest ears grain weightmoisture content
forecast stalksears ear shootsears with kernels historical averagekernel row lengthear diameterear weight
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Gross Yield Components

• SOYBEANS

plants per acre x pods per plant bean weight per pod
at harvest plantspods bean weightmoisture content
forecast plantsmain stem nodeslateral branchesblooms, dried flowers podspods with beans historical averagelateral branchespods with beanspod weight
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Gross Yield Components

• COTTON

bolls per acre lint weight per boll
at harvest open bollslarge bolls lint weightmoisture content
forecast squaresbloomsbollsburrs historical averagebloomsbollslarge boll weight
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Gross Yield Components

• POTATOES

hills per acre potato weight per hill
at harvest hills potato weight
forecast
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Harvest Loss Component
gross yield gross yield gross yield harvest loss
after harvest gleanings
forecast historicalaverage
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• Forecasting the futureis dependent onpatterns
  of the past...

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Objective Yield Forecasting

• Current Counts Measurements
• Historical Data Models
• Counts Measurements ? Final Yield
• Forecast

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Objective Yield Model 1
Number of Fruit
Weight per Fruit
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Objective Yield Model 2
Early Season Yield Forecast
150
07
140
05
09
130
99
00
03
98
02
120
95
08
NASS yield
97
04
110
y 0.0013x - 76.025
06
100
90
01
96
80
120000
130000
140000
150000
160000
170000
independent variable
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Yield Survey Indications

• Objective Yield 1
• regress sample level counts /or measurements to
  final crop-cutting data
• forecast yields for each sample
• average sample level yields to state regional
  forecasts
• overestimates
• Objective Yield 2
• aggregate sample counts /or measurements to
  state region independent variable
• regress independent variable to final NASS yield
• unbiased estimates
• Agricultural Yield
• summarize grower reported yields using sampling
  weights
• underestimates

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Yield Forecasting Process

• regress Objective Yield1 Agricultural Yield
  indications to final NASS yield
• determine prediction intervals for each
  regression ( 1 SE)
• determine the overlap of the three prediction
  intervals
• use expert knowledge to decide where within the
  overlap intervalto set forecast

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Analyzing Yield Data

• survey data
• impact of unusual reports
• maturity stages
• yield components
• other data relationships
• crop progress reports
• planting dates
• pollination dates
• weather data
• rainfall
• heat degree days
• industry contacts
• insect problems
• disease problems

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Reliability of U.S. Crop Production Forecasts
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Reliability of U.S. Crop Production Forecasts
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Grain Oilseed Stocks Surveys
Off-farm On-farm
sample sample
commercial grain storage operations elevators warehouses terminals grain oilseed processing plants other storage facilities not classified as farms farms in Agricultural Surveys
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Grain Oilseed Stocks Surveys
Off-farm On-farm
data obtained data obtained
all whole (unprocessed) grains oilseeds on hand or stored in permanent or temporary facilities regardless of ownership or intended use all whole (unprocessed) grains oilseeds on hand or stored in permanent or temporary facilities regardless of ownership or intended use
data collection modes data collection modes
mail questionnaire Internet questionnaire telephone interview personal interview mail questionnaire Internet questionnaire telephone/CATI interview personal interview
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Grain Oilseed Prices Surveys

• sample
• firms that purchase whole grains oilseeds from
  farmers
• 30 States in monthly program account for 90 of
  all U.S. sales
• data obtained
• quantity purchased from farmers during previous
  month
• total dollars paid for this quantity
• including quality discounts premiums,
• excluding deductions for drying, handling,
  cleaning, storage, grading, checkoff fees, etc.
• data collection modes
• mail questionnaireInternet questionnaire
• telephone interview
• personal interview

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Crop Progress Condition Surveys

• monthly Crop Production reports
• issued on or about 10th day of each month
• reflect conditions as of 1st day of month
• weekly Crop Progress Condition reports
• issued 1st business day of each week,
  April-November
• reflect status conditions as of previous Sunday
• farmer activities, such as planting and
  harvesting
• progress of crops through various phenological
  stages of development
• crop, pasture range conditions
• soil moisture ratings

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Crop Progress Condition Coverage
Crop progress conditionbarley, corn, cotton, peanuts, oats, rice,sorghum, soybeans, sugarbeets, sunflowers,winter wheat, spring wheat States that account forat least 75 of areaplanted to crop of interest
Pasture range condition all States except Alaska Hawaii
Soil moisture days suitable for field work all States except Alaska, Arizona, California, Hawaii Nevada
Narrative all States
At least one reporter for each agricultural county in each State At least one reporter for each agricultural county in each State
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Corn Progress Condition
18 states account for 92 of acres planted to
corn in 2009
planted emerged silk dough dent mature harvested c
ondition
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Soybean Progress Condition
18 states account for 95 of acres planted to
soybeans in 2009
planted emerged bloom set pods drop
leaves harvested condition
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Winter Wheat Progress Condition
18 states account for 89 of acres planted to
winter wheat for 2010
planted emerged headed harvested condition
48
Spring Wheat Progress Condition
6 states account for 99 of acres planted to
spring wheat in 2009
planted emerged headed harvested condition
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Cotton Progress Condition
15 states account for 99 of acres planted to
cotton in 2009
planted squaring set bolls bolls
open harvested condition
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Other Crops Progress Condition
numberofStates of2009plantedarea progress stages
Barley 5 81 planted, emerged, headed, harvested, condition
Oats 9 64 planted, emerged, headed, harvested, condition
Peanuts 8 98 planted, pegging, harvested
Rice 6 100 planted, emerged, headed, harvested, condition
Sorghum 11 98 planted, headed, coloring, mature, harvested, condition
Sugarbeets 4 84 planted, harvested
Sunflowers 4 85 planted, harvested
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Crop Progress Condition Reporters

• 5,000 reporterswhose occupations provide
  frequent opportunitiesto observe crops and/or
  contact farmers in their counties
• Extension Service agents
• USDA Farm Service Agency directors
• NASDA enumerators
• Agribusiness representatives
• Crop advisors
• Farmers

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Crop Progress Condition Data Collection

• mail
• phone
• fax
• personal interview
• e-mail
• Internet
• 80-85

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Crop Progress Condition Questionnaire

• Required items specified weekly by HQ
• historical trends at national level
• current trends at national level
• rules
• States may deviate from requirements
• start earlier or end later for particular items
• additional items of interest to State
• All questions must use standardized wording!

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Crop Progress Condition Summary Analysis

• County averages weighted by planted areasto
  State-level estimates
• State estimates weighted by planted areasto U.S.
  estimates
• State U.S. progress estimates compared
  withlast week, last year and 5-year average
• within-season progress cannot go backwards
• unusually large or small changes must be
  explained

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Crop Progress Condition Reports
issued at 1200 Eastern2nd business day of week
issued by World Agriculture Outlook
Boardafternoon 2st business day of week
issued at 1600 Eastern1st business day of week
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Crop Progress Condition Uses Users

• producers
• agribusinesses
• commodities traders
• government agencies
• researchers
• assess current growing conditionsin order to
  reduce inherent risks of doing business
• planning, decision-making, research
• NASS
• interpretation of survey results for crop yield
  forecasts