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Learn about restricted neighbor imputation method applied to Norwegian Agriculture Survey for reliable statistics. Explore objective, method, empirical results, and future work.
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Statistical registers by restricted neighbor imputation – An application to the Norwegian Agriculture Survey Nina Hagesæther and Li-Chun Zhang Statistics Norway
Outline • Objective • Method • Empirical results • Future work
Objective • Statistical register: Variables Known Known Units Unknown Known
Statistical register: Objective Register variables Good quality Known Known Units Unknown Poor quality Known Known 4
Statistical register: Objective Register variables Target variables Units in sample Known Known Units outside sample Unknown Known 5
Objective • Triple-goal criterion (Zhang and Nordbotten, 2008) • Efficient estimates • Correct covariance structure • Non-stochastic
The RENI Method • REstricted Neighbor Imputation • Restrictions: Totals are already estimated • Donors = respondents • Receivers = population – respondents • Nearest neighbor (NN) = unit in same imputation class that satisfy
Algorithm • Fine-tune phase (FT) • Donor among k nearest neighbors • Choose the donor that best satisfy the restrictions • An iterative process • Jump-start phase (JS) • NN imputation for a given proportion of totals • Speeds up the process • Proportion can be reduced or JS omitted
Agriculture Survey 2006 • 50 000 units in the population, 10 000 in the sample • 84 target variables • Publish: class of farmlands in decares (6), farming activity (FA, 12), county • Important topics: leasing, investment, maintenance
Empirical results – Number of neighbors FA- 2: 2660 receivers, 727 donors FA- 4: 9984 receivers, 3266 donors FA-10: 384 receivers, 243 donors FA-11: 586 receivers, 340 donors
Empirical results (FA-4) – Restriction Donors: 3000, Receivers: 10000 Alt 1: Equal weight for all 84 restrictions when calculating delta (84) (84) (12) Alt 2: Chosen 12 restrictions 10 times higher weights Alt 3: 9 sets of sub-population restrictions in addition to alternative 2 (12x10) 11
Empirical results (FA-10) – Restriction Donors: 240, Receivers: 380 Alt 1: Equal weight for all 84 restrictions when calculating delta (84) (12) Alt 2: Chosen 12 restrictions 10 times higher weights Alt 3: 9 sets of sub-population restrictions in addition to alternative 2 (12x10) 12
Empirical results - Correlations Farmingactivity 10
Future work • Restriction • How to choose restrictions • How to calculate delta • Adjust for partial non-response • Donor and receiver do not match on observed values of receiver • Partial missing in target variables • Unit missing of target variables as partial missing of combined auxiliary and target variables
Thank you for your attention! Statistics Norway in Kongsvinger Statistics Norway in Oslo
Empirical results – Computation time Farming activity 4 Farming activity 10
Empirical results – Two-way classification Farmingactivity 10