A UBC researcher has asked about a number of dissemination areas in the Vancouver CMA that are missing from the DA Profile table. Both he and I have looked at population counts; the counts for DAs on his list range from 396 to 3067 and the numbers of occupied dwellings range from 138 to 1385. These numbers are from GeoSuite 2006. They all exceed the 40 households / 250 persons suppression rules.
He has asked where he can find an explanation for the missing areas. I checked several DAs on the reference maps. Two DAs appear to contain student residences here at UBC; another one with a population of 2795 is in an area where many condominiums have been built in recent years.
Is it possible to find an explanation?
Here is his list of missing DAs
Thanks for any help you can provide. I will be interested in the reasons.
Our Census Consultants have indicated that "Simply put, the suppression is due to poor data quality caused by a high non-response rate in these areas." They also provided this detailed explanation:
"These DAs have data quality flags that can lead to suppression. Data quality indicators, or data quality flags, are attached to each geographic area disseminated. The 5-digit flag can be seen directly in the Beyond 20/20 browser, and is indicated by notes and symbols in HTML products. The second and fourth positions indicate the data quality flag for 2A and 2B data respectively. A flag of 0 is the default. Flag 1 indicates a global non-response rate higher than or equal to 5% and less than 10%. Flag 2 indicates a global non-response rate higher than or equal to 10% but less than 25%. For both of these cases, data are disseminated but should be used with the appropriate caution. Flag 3 indicates a global non-response rate greater than or equal to 25% and data for these areas are suppressed because the data quality is deemed too poor to be reliable. I checked the cumulative profile product at the DA level (which I also suspect is what your client is looking at) and all of these DAs are suppressed correctly as noted above.
For complete suppression lists please see the following link: http://www12.statcan.ca/census-recensement/2006/ref/notes/index-eng.cfm
From the Census Home Page select Reference materials > Notes > Dissemination area suppression list including census subdivisions in which they are located - 100% data or Dissemination area suppression list including census subdivisions in which they are located - 20% sample data"
I hope that this helps. Please let me know if you have any other questions.
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