Intuitively we would expect that the major impact of SCAM would be on Output Area (OA) flows since OAs are the smallest spatial units.
How do we assess the impact at this scale? Difficult because of the huge volume of potential flows involved and the sparse matrices that will contain very large numbers of origin-destination pairs between which there is no interaction flow.
In theory, if we take total migrants, the potential matrix of adjusted inter-area flows is 223,060 origins and 180,456 destinations which is over 40 billion cells! There are only 180,456 destinations because flows with destinations in Scotland have not been disclosure controlled.
If we consider Table MG301(Total migrants by age and sex), ONS only provide data on OA to OA flows for cells 5 and 6, 8 and 9, 11 and 12 where the flow is non-zero.
The totals in cells 1, 2,3,4, 7 and 10 and all based on aggregations of the interior cells.
So what is the frequency of the counts included in this table?