What you should know

A. Cell suppression and reliability of small data cells

Cell suppression has been applied to the tables as necessary to take into account the lower reliability of data for smaller sample sizes. (Refer to the “Methodology” section for more information on suppression and data quality). In certain cases, particularly where the geographic area covered is small in terms of population or where any other characteristic used to define the population is rare, this results in small sample sizes and as a result, the reliability of the statistic may be too low to publish. Suitable rules of reliability were used to screen the data.

In a few table views, the number of suppressed data points may make the entire table view somewhat unusable. While the tables could have been designed to eliminate certain categories or dimensions from the outset, this would most likely mean simultaneously eliminating some usable content. Instead, the approach has been to include all views of the table (no elimination of any categories of any dimensions), and rely on cell-by-cell data suppression to screen data that are not reliable.

B. SLID population estimates

The 900 series “Background tables” provide SLID population estimates of the number of individuals and economic/census families for Canada, provinces and selected CMAs. Users should be aware that these SLID estimates differ from official Statistics Canada population estimates. Unlike official population estimates, there are many segments of the population that are not included in the SLID survey, including residents of the Yukon, the Northwest Territories and Nunavut, residents of institutions and persons living on Indian reserves. Overall, these exclusions amount to less than three percent of the population.

C. Missing values for characteristics other than income

Both SLID and the SCF have complete data on all respondents for age, sex, family relationships and income characteristics. However, only the SCF has complete data without missing values for all labour market characteristics and education since the SCF was conducted as a supplement to the Labour Force Survey, which provided the base labour data entirely edited and imputed. To the extent that there are missing values in a dimension, identified as the category "unknown", there could be an undercount in any or all of the other categories. If the undercount in SLID is substantial, a break could appear between the two periods (the period up to 1995 and the period since 1996).