Question
I have a researcher asking why Census Tract 058 in Vancouver (Code: 59 933 0058) is suppressed in 2011, but not in 2006. You can find 2011 population, private dwellings, density, and land area for this tract, but no other statistics (age, sex, marital status, etc). With a 2011 population of 3792, shouldn’t there be enough data to produce these statistics for this Census Tract?
The only other Vancouver Census Tract that shows no 2011 statistics is 59 933 0270, but it appears the same was true in 2006. And the population in 2011 was 5, so suppression makes sense. Not so for Tract 058.
Answer
Looking in the IVT file notes under the Geography tab...they can view the data quality flag descriptions. For this CT there is a 3 in the second spot (03000).
Notes:
2011 Census – Data quality flags and descriptions
Data quality flags for place of residence
Digit Description
1st (0XXXX) Incomplete enumeration flag
2nd (X0XXX) Data quality flag
3rd (XX0XX) Population and dwelling counts error flag
4th (XXX0X) Not applicable
5th (XXXX0) 2006 adjusted population flag
Flag description
Data quality flag
0 = Default.
1 = Data quality index showing, for the short census questionnaire (100% data), a global non response rate higher than or equal to 5% but lower than 10%.
2 = Data quality index showing, for the short census questionnaire (100% data), a global non response rate higher than or equal to 10% but lower than 25%.
3 = Data quality index showing, for the short census questionnaire (100% data), a global non response rate higher than or equal to 25% (suppressed).
Global response rates
Global response rates are determined for each of the census geographic areas. These areas are flagged on the database according to the non-response rate. Geographic areas with a non-response rate higher than or equal to 25% are suppressed from tabulations. Geographic areas with a global non-response rate higher than or equal to 5% and lower than 25% are broken into two categories and are flagged according to the following ranges: falling between 5% and 10% and falling between 10% and 25%. These geographic areas are identified in tabulations, but not suppressed. In electronic products, a numeric flag is provided with the area identifier indicating low data quality.
In 2006 the following data quality notes were applied to the same CT for the 2A Census hence why there are results in 2006.
Data quality index showing, for the short census questionnaire (100% data), a global non response rate higher than or equal to 10% but lower than 25%.
For more information regarding Data quality flags, they can consult the Data Quality and Confidentiality Standards and Guidelines (Public) guide: <http://www12.statcan.gc.ca/census-recensement/2011/ref/DQ-QD/qual-eng.cfm>
