Question
When I access the 2011 census tract profiles for London CMA, I am seeing some problems with the numbers, specifically with Age Characteristics.
If you go here, I can describe what I mean:
<http://www12.statcan.gc.ca/census-recensement/2011/dp-pd/prof/details/page.cfm?Lang=E&Geo1=CSD&Code1=3539036&Geo2=CT&Code2=1745&Data=Count&SearchText=5550045.00&SearchType=Begins&SearchPR=01&B1=All&Custom=&TABID=1>
Here are a couple of errors I have noticed for 5550045.00 profile:
Age characteristics 17 years: Total 5/Male 5/Female 5
18 years: Total 25/Male 10/Female 20
40-44 years: Total 30/15/10
The math does not seem to be adding up.
Answer
This is a rounding technique to ensure confidentiality, for more information please see
Data Quality and Confidentiality Standards and Guidelines (Public)
<http://www12.statcan.gc.ca/census-recensement/2011/ref/DQ-QD/conf-eng.cfm>
1. When a sum is specified for age, then the program multiplies the unrounded average of the group in question by the rounded frequency. Otherwise, if a sum is specified for a variable other than age, the program rounds the actual sum.
