Using Models to Estimate Hog and Pig Inventories Proceedings of a Workshop (2019) / Chapter Skim
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10 Discussion of State-Level Estimation
10 Discussion of State-Level Estimation
Pages 69-78
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From page 69... ...
In addition, state recommendations are developed with state-level survey data adjusted by regional offices. For these data sources, variables available include sows farrowed and pig crop (available monthly)
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From page 70... ...
Slaughter data are available monthly at the national level. Data on number of hogs slaughtered in a state are available monthly based on slaughterhouse location, but those data do not reflect where the hog was raised so are not comparable to NASS hog inventory data.
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From page 71... ...
Another key question is how to compute variance estimates in this complex process with multiple types of error: modeling error, sampling error, imputation, and judgment. SMALL AREA ESTIMATION Before moving on to the two presentations about small area estimation, Slud asked about the sample sizes in small and large states to get a better idea about the range of sampling errors.
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From page 72... ...
The sampling model describes the sample estimate as providing an unbiased estimate for state production, ϴi, with an additive noise term. The noise term has zero mean and is normally distributed, with variance equal to the sampling variance.
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From page 73... ...
He observed that some of these approaches also work with short time series, such as the 10 years of quarterly data discussed. Many survey and nonsurvey variables can be put together in a model to borrow strength over both time and small areas.
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From page 74... ...
These might be measured with error, in which case a measurement error model should be included. This is another way to borrow strength that has worked in other small area contexts using survey data.
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From page 75... ...
Dan Kerestes said there are not enough instances of this occurring to be useful, noting that the states surveyed annually contribute less than 0.5 percent of the national pig crop. Plain referred to Sartore's discussion about estimating pig survival rates and death loss by state.
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From page 76... ...
Lee Schulz asked whether the process that transforms the survey data into state recommendations is consistent across states, model-based, and uses expert judgment. Kerestes replied 12 regional offices set the state-level recommendations.
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From page 77... ...
What NASS tries to do, however, is to capture shifts in the hog industry at the national level.
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From page 78... ...
Ensor asked how often hog operations come in and go out of business during a 5-year period and whether dramatic shifts in the overall structure of hog production occur from one 5-year period to the next. Young referred to previous discussion (see Chapter 4)
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