Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression...
Transcript of Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression...
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Cell suppression in a special class oflinked tables
Peter-Paul de Wolf
Statistics Netherlands
December 17, 2007Manchester, Great Brittain
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Contents
Introduction
HierarchiesTreesPure subCoveringLinking
ProblemsExampleNotes
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Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Introduction
Cell suppressionStand alone tableHierarchically linked tables
Subset of generally linked tablesHierarchically linkedDifferent detail of same hierarchy
5-digit NACE code × high level region2-digit NACE code × detailed region5-digit NACE code × detailed region
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Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Introduction
Cell suppressionStand alone tableHierarchically linked tablesSubset of generally linked tables
Hierarchically linkedDifferent detail of same hierarchy
5-digit NACE code × high level region2-digit NACE code × detailed region5-digit NACE code × detailed region
![Page 5: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/5.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Introduction
Cell suppressionStand alone tableHierarchically linked tablesSubset of generally linked tables
Hierarchically linkedDifferent detail of same hierarchy
5-digit NACE code × high level region2-digit NACE code × detailed region5-digit NACE code × detailed region
![Page 6: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/6.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Introduction
Cell suppressionStand alone tableHierarchically linked tablesSubset of generally linked tables
Hierarchically linkedDifferent detail of same hierarchy
5-digit NACE code × high level region2-digit NACE code × detailed region
5-digit NACE code × detailed region
![Page 7: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/7.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Introduction
Cell suppressionStand alone tableHierarchically linked tablesSubset of generally linked tables
Hierarchically linkedDifferent detail of same hierarchy
5-digit NACE code × high level region2-digit NACE code × detailed region5-digit NACE code × detailed region
![Page 8: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/8.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Introduction
Cell suppressionStand alone tableHierarchically linked tablesSubset of generally linked tables
Hierarchically linkedDifferent detail of same hierarchy
5-digit NACE code × high level region2-digit NACE code × detailed region5-digit NACE code × detailed region
![Page 9: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/9.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Hierarchies
Need way to define set of linked tables
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Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Hierarchies as trees
S A A1
A2
B B1
B2 B21
B22
C C1
C2 C21
C22
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Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Pure sub hierarchies
G H1 H2 H3
S A A1
A2
B B1
B2 B21
B22
C C1
C2 C21
C22
S A
B
C C1
C2
S A1
A2
B1
B2
C1
C2
S A
B
H1 � G H2 6� G H3 6� G
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Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Pure sub hierarchies
G H1 H2 H3
S A A1
A2
B B1
B2 B21
B22
C C1
C2 C21
C22
S A
B
C C1
C2
S A1
A2
B1
B2
C1
C2
S A
B
H1 � G H2 6� G H3 6� G
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Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Covering hierarchies
G covers the set of hierarchies (H1, . . . ,HK )
if
G is the smallest hierarchy with
Hi � G ∀i = 1, . . . , K
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Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Defining linked tables
User specifies N tables to be protectedTables can be hierarchical
All hierarchies of same variable should be coverable!
Tables have M different spanning variablesDefine M-dimensional table with hierarchies coveringuser defined hierarchiesUse modular approach, disregarding subtables not inuser set of tables
![Page 15: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/15.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Defining linked tables
User specifies N tables to be protectedTables can be hierarchical
All hierarchies of same variable should be coverable!
Tables have M different spanning variablesDefine M-dimensional table with hierarchies coveringuser defined hierarchiesUse modular approach, disregarding subtables not inuser set of tables
![Page 16: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/16.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Defining linked tables
User specifies N tables to be protectedTables can be hierarchicalAll hierarchies of same variable should be coverable!Tables have M different spanning variablesDefine M-dimensional table with hierarchies coveringuser defined hierarchiesUse modular approach, disregarding subtables not inuser set of tables
![Page 17: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/17.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Defining linked tables
User specifies N tables to be protectedTables can be hierarchicalAll hierarchies of same variable should be coverable!Tables have M different spanning variablesDefine M-dimensional table with hierarchies coveringuser defined hierarchiesUse modular approach, disregarding subtables not inuser set of tables
![Page 18: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/18.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Defining linked tables
User specifies N tables to be protectedTables can be hierarchicalAll hierarchies of same variable should be coverable!Tables have M different spanning variablesDefine M-dimensional table with hierarchies coveringuser defined hierarchiesUse modular approach, disregarding subtables not inuser set of tables
![Page 19: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/19.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Defining linked tables
User specifies N tables to be protectedTables can be hierarchicalAll hierarchies of same variable should be coverable!Tables have M different spanning variablesDefine M-dimensional table with hierarchies coveringuser defined hierarchiesUse modular approach, disregarding subtables not inuser set of tables
![Page 20: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/20.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Problems
Implicitly defined structure is not protected explicitly
Set of tables completely determines interior of higherdimensional table
![Page 21: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/21.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Problems
Implicitly defined structure is not protected explicitly
Set of tables completely determines interior of higherdimensional table
![Page 22: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/22.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Example of problem
B1 B2 B3 Total C1 C2 C3 TotalA1 30 150 70 250 A1 140 50 60 250A2 270 110 255 635 A2 85 210 340 635
Total 300 260 325 885 Total 225 260 400 885
Safe! Safe!
C1 C2 C3 TotalB1 110 90 100 300B2 40 50 170 260B3 75 120 130 325
Total 225 260 400 885
Safe!
However:interior A× B × C is unique!Any unsafe cell in interior is implicitly disclosed!
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Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Example of problem
B1 B2 B3 Total C1 C2 C3 TotalA1 30 150 70 250 A1 140 50 60 250A2 270 110 255 635 A2 85 210 340 635
Total 300 260 325 885 Total 225 260 400 885Safe! Safe!
C1 C2 C3 TotalB1 110 90 100 300B2 40 50 170 260B3 75 120 130 325
Total 225 260 400 885Safe!
However:interior A× B × C is unique!Any unsafe cell in interior is implicitly disclosed!
![Page 24: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/24.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Example of problem
B1 B2 B3 Total C1 C2 C3 TotalA1 30 150 70 250 A1 140 50 60 250A2 270 110 255 635 A2 85 210 340 635
Total 300 260 325 885 Total 225 260 400 885Safe! Safe!
C1 C2 C3 TotalB1 110 90 100 300B2 40 50 170 260B3 75 120 130 325
Total 225 260 400 885Safe!
However:interior A× B × C is unique!Any unsafe cell in interior is implicitly disclosed!
![Page 25: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/25.jpg)
Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Similarly: suppression pattern can be broken
Problem may also occur in current situationUsed hierarchy not complete detail
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Contents
Introduction
HierarchiesTrees
Pure sub
Covering
Linking
ProblemsExample
Notes
Similarly: suppression pattern can be broken
Problem may also occur in current situationUsed hierarchy not complete detail
![Page 27: Cell suppression in a special class of linked tables€¦ · Notes Introduction Cell suppression Stand alone table Hierarchically linked tables Subset of generally linked tables Hierarchically](https://reader034.fdocuments.us/reader034/viewer/2022042919/5f605472ba42056244693952/html5/thumbnails/27.jpg)
Thank you.