Field Crop Reporting Series
Detailed information for September 2014
Status:
Active
Frequency:
6 times per year
Record number:
3401
The purpose of this set of farm surveys is to obtain information on grains and other field crops stored on farms (March, July, September and December Farm surveys), seeded area (all surveys except December Farm survey), harvested area, expected yield and production of field crops (July, September and November Farm surveys).
Data release - October 3, 2014
Description
This is a series of six data collection activities which are used in the release of estimates at pre-scheduled, strategic times during the crop year.
These data are meant to provide accurate and timely estimates of seeding intentions, seeded and harvested area, production, yield and farm stocks of the principal field crops in Canada at the provincial level. The crops surveyed include wheat, oats, barley, rye, flaxseed, canola, corn for grain, soybeans, sunflower seed, dry beans, dry field peas, lentils, mustard seed, Canary seed and chick peas.
The data are used by Agriculture and Agri-food Canada and other federal departments to develop and administer agricultural policies. This information is also used by provincial departments for production and price analysis and for economic research.
Reference period: Seeded area (all occasions); harvested area, yield and production ( July, September, November); stocks (calendar year end (December), financial year end (March), crop year end (July/September)).
Collection period: Collection period for each survey occasion starts approximately 4 weeks prior to the release of the results, and lasts 6 to 10 days, depending on the size of the sample.
Subjects
- Agriculture and food (formerly Agriculture)
- Crops and horticulture
Data sources and methodology
Target population
The target population for the Farm Surveys includes all farms in Canada enumerated in the Census of Agriculture except institutional farms, farms on First Nations reserves and farms from the Northwest Territories, Yukon and Nunavut.
Farm surveys collect data from Quebec, Ontario, Manitoba, Saskatchewan and Alberta at all survey occasions. However they only collect data twice a year (in the June Farm survey on seeded areas and in the November Farm survey on final crop production) for Newfoundland and Labrador, Prince Edward Island, Nova Scotia, New Brunswick and British Columbia.
Instrument design
The questionnaire was originally designed in 1908, and has evolved over the years in order to address Statistics Canada and Canadian agricultural requirements. Consultations have taken place between subject matter specialists and provincial and industry experts. Testing is conducted in-house for flow and consistency. Questions will be changed, added or removed as the need arises.
Sampling
This is a sample survey with a cross-sectional design.
Probability surveys can use two types of sampling frames: list and area. In the Farm Surveys, only the list frame is used in sample selection. This list frame is stratified into homogenous groups on the basis of Census characteristics (such as farm size and crop area) and sub-provincial geographic boundaries.
Sample size varies for each survey instance:
March - approximately 11,500 farms
June - approximately 24,500 farms
July - approximately 13,100 farms
September - approximately 9,300 farms
November - approximately 26,800 farms
December - approximately 8,600 farms
Data sources
Responding to this survey is mandatory.
Data are collected directly from survey respondents.
Data are collected by Computer assisted telephone interview (CATI) from the regional offices and transferred electronically to headquarters in Ottawa. No further follow-up is done.
View the Questionnaire(s) and reporting guide(s).
Error detection
With the CATI system, it is possible to implement edit procedures at the time of the interview. Computer programmed edit checks in the CATI system inform interviewers during the interview of possible data errors, which can then be corrected immediately by the interviewer and respondent. CATI significantly reduces the need for subsequent telephone follow-up, thereby reducing respondent burden and survey processing time.
Data are then compared on a year-to-year basis. Analysts cross check each other's work and group reviews are performed. All top contributors are also reviewed.
Imputation
Imputation is only done for yield for the production surveys (July, September and November Farm surveys), using an average yield by crop calculated from all complete records in a given crop district. The average is imputed into records with missing values for yield.
Estimation
Information applicable to all surveys:
The survey data collected are weighted in order to produce unbiased level indicators which are representative of the population. Also from two level indicators, it is possible to derive unbiased ratio indicators such as the pair change ratio of the seeded acreage from year to year. These level indicators then undergo a validation process, based on subject matter analysis, before final estimates are published.
Since March 2014, for response burden matters, the operations that, all together, have a total cropable land lower than a provincial threshold are excluded from Farm survey samples (null sampling). This threshold, which varies from one province to the other, is such that all farms having an area greater than the threshold itself represent, all together, 95% of the total cropable land of a given province. The estimate share of the non-surveyed farms is then modelled and added to the estimation derived from surveyed farms, in order to draw a complete picture of field crop areas or productions.
The March Farm Survey estimates farmers' seeding intentions. In June, preliminary seeded acreage results are published and in November the estimates are revised with information from the fall surveys.
The July, September and November Farm surveys provide data on the harvested area, average yield and production of crops on farms. The survey data are weighted to estimate production at the provincial and crop district levels. The level indicators are established for production and harvested acreage. From these two indicators, the average yield for the crop district or province is calculated.
Information applicable to surveys collecting data on farm stocks:
Farm stocks are estimated at December 31, March 31, July 31 and August 31. Several level indicators are produced from the stocks surveys, including harvested area, farm stocks and production. Also various ratio indicators are derived using the level indicators.
A major tool used in the verification of these estimates is the farm supply-disposition (or supply-demand) balance sheet. This table reflects activity on farm only before grain enters the commercial system. The supply and disposition numbers must be equal.
The supply is composed of opening farm stocks and production. The disposition is comprised of deliveries, seed use, closing farm stocks as well as feed, waste and dockage. The production and farm stocks are estimated from Farm Surveys conducted by Statistics Canada. Seed use data are based on average seeding rates. A major portion of the deliveries are licensed grain deliveries obtained from the Canadian Grain Commission (CGC). The "feed, waste and dockage (fwd)" component is a residual in the balance sheet. Indicators such as the number of grain consuming animal units, harvest conditions affecting grain quality, established ratios of dockage to delivered grain and grain inspections are used to ensure data accuracy.
National supply and disposition tables provide further information to aid in estimating farm stocks.
Quality evaluation
The estimates are based on level indicators obtained from a probability survey of farming operations. The potential error introduced by sampling can be estimated from the sample itself by using a statistical measure called the "coefficient of variation" (c.v.). Over repeated surveys, 95 times out of 100, the relative difference between a sample estimate and what should have been obtained from an enumeration of all farming operations would be less than twice the c.v.. This range of values is referred to as the "confidence interval". While published estimates may not exactly equal the level indicators due to the validation, these estimates do remain within the confidence interval of the survey level indicators. For the July Farm Survey, c.v.'s range from 2% to 10% for the major crops. Coefficients of variation for specialty crops are usually within 11% to 25%.
The survey results are also evaluated through comparisons to previous estimates and other sources when available. Market and growing conditions for crop production are used as a guide when evaluating the data.
Totals may not equal the sum of their parts due to the use of conversion factors or rounding of fractions to whole numbers.
Disclosure control
Statistics Canada is prohibited by law from releasing any information it collects that could identify any person, business, or organization, unless consent has been given by the respondent or as permitted by the Statistics Act. Various confidentiality rules are applied to all data that are released or published to prevent the publication or disclosure of any information deemed confidential. If necessary, data are suppressed to prevent direct or residual disclosure of identifiable data.
In order to prevent any data disclosure, confidentiality analysis is done using the Statistics Canada Generalized Disclosure Control System (G-Confid). G-Confid is used for primary suppression (direct disclosure) as well as for secondary suppression (residual disclosure). Direct disclosure occurs when the value in a tabulation cell is composed of or dominated by few enterprises while residual disclosure occurs when confidential information can be derived indirectly by piecing together information from different sources or data series.
Revisions and seasonal adjustment
Seeded areas published from the June Farm survey represent preliminary estimates and can be changed over the course of the crop year. Field crop production estimates are evaluated in July (before harvest), in September (during harvest) and one last time in November (after harvest). These estimates published at the end of the crop year are then subject to change for 2 years, and to intercensal revisions if applicable.
Data accuracy
The field crops statistics are based on a random sample of agricultural operations and, as such, are subject to sampling and non-sampling errors. The overall quality of the estimates depends on the combined effect of these two types of errors.
Sampling errors arise because estimates are derived from sample data and not from the entire population. These errors depend on factors such as sample size, sampling design and the method of estimation. An important feature of probability sampling is that sampling errors can be measured from the sample itself.
Non-sampling errors are errors which are not related to sampling and may occur throughout the survey operation for many reasons. For example, non-response is an important source of non-sampling error. Coverage, differences in the interpretation of questions, incorrect information from respondents, mistakes in recording, coding and processing of data are other examples of non-sampling errors.
Usually by the end of the collection period, 80% of the questionnaires have been fully completed. The refusal rate to the survey is approximately 8% to 9%. The remainder of the sample unaccounted for can be explained by non-contact and non-response. Initial sample weights are adjusted by a process called "raising factor adjustment" in cases of total or partial non-response.
Since July 2013, estimates displayed on CANSIM or in The Daily for the provinces of Newfoundland and Labrador, Prince Edward Island, Nova Scotia, New Brunswick and British Columbia are derived from survey data in June and November occasions, but are carried over from the most recent time they were surveyed for the other occasions, i.e. from the preceeding November occasion for March occasion, and from the preceeding June occasion for July and September occasions.
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