Core Inflation Rate YoY

Core Inflation Rate YoY (12-month % change versus the same month 1 year earlier) tracks Canadian price moves through 3 gauges that replaced CPIX. Statistics Canada publishes three national gauges from the CPI (Consumer Price Index): CPI-trim, CPI-median and CPI-common. Trim averages the middle 60% of monthly moves; median picks the move at 50% of basket weight; common tracks the shared move. Core is not headline inflation; it filters short-lived swings and the Bank of Canada judges it against a 2% midpoint in a 1-3% range.

Prices cover one reference month: mostly the first 2 weeks, food into the 3rd week, stable items less often. The result comes monthly at 8:30 Eastern, about 3 weeks after the reference month, typically on the 3rd Wednesday. Each release gives year-over-year % change with an analytical text plus headline, provincial, seasonally adjusted and core tables, and names the next date. Unadjusted CPI is never revised; trim and median revise back 7 years, common revises with history, and the Bank avoids mechanical use.

The basket splits into 8 major groups; shares below are the 2024 basket at April 2025 prices, one vintage, not fixed weights.

• Shelter, 29.41%: rent, mortgage interest and replacement costs, taxes, insurance and maintenance.
• Food, 16.91%: groceries and restaurant food, including volatile fresh items.
• Transportation, 16.90%: vehicle purchase and rental, gasoline (3.23% alone) and local and inter-city transportation.
• Household operations, furnishings and equipment, 13.25%: communications, child care, cleaning, furniture and appliances.
• Recreation, education and reading, 10.12%: recreation equipment and services, travel, culture and education.
• Clothing, health, alcohol and tobacco, 13.42%: garments, footwear, health and personal care, alcohol, tobacco and cannabis.

The March 2017 release (published 21 April 2017) showed headline at 1.6%, down from 2.0%, with ex-food-and-energy at 1.7%, down from 2.0%. CPI-common held at 1.3%, CPI-median eased to 1.7% and CPI-trim to 1.4%, while transport rose 4.6% and shelter contributed most. Food and clothing fell and household operations were flat, while seasonally adjusted CPI fell 0.2% as transport dropped 1.1%. Recreation, education and reading rose 0.6%, while headline noise contrasted with steady core that the Bank looks through.

1. Elementary index: For each of about 645 product classes in 19 regions, combine matched price relatives with a Jevons geometric mean. About 75% of weight uses observed prices; the rest is imputed (filled in).
2. Upper aggregation: Aggregate them with a Lowe fixed-basket formula using Survey of Household Spending weights; base period is 2002 = 100.
3. Year-over-year change: Compare a month with the same month 1 year earlier: YoY = ((Index now minus Index year-ago) / Index year-ago) x 100. Index 123.4 means prices up 23.4% since the 2002 base.
4. CPI-trim: Seasonally adjust the 55 tax-removed indexes, rank rates with basket weights, and drop the bottom 20% and top 20% of weight. Average the retained middle 60% by weight for the monthly rate, then compound 12 monthly rates into the annual (year-over-year) rate.
5. CPI-median: Use the same ranked list, then pick the rate at 50% of cumulative basket weight as the monthly median rate. Compound the 12 monthly median rates exactly like trim to get the annual (year-over-year) rate.
6. CPI-common: Use unadjusted year-over-year rates, standardize history (subtract mean, divide by standard deviation), and take the 1st principal component, the factor best explaining joint moves. Scale the factor to inflation units by regressing (fitting) total CPI year-over-year (excluding indirect taxes) on it; fitted values are CPI-common.
7. Simplified example: In a 5-component illustration, the median is B 0.2% and the trimmed monthly average is 0.225%. If every monthly trimmed rate were 0.15%, compounding 12 months gives about 1.8% annually.