Late Index Methodology
This page documents the exact formula, data sources, interpretation thresholds, and limitations of the Tardif Index. It is updated with each methodological revision.
1. The General Formula
The Tardif Index is calculated using a weighted formula that combines three market components, each converted into a sub-score from 0 to 100.
The weighting reflects the relative importance of each signal: the SNLR is the best indicator of instantaneous market tension, the expiration ratio captures the adequacy between asking prices and market reality, and annual momentum captures cyclical dynamics.
Component 1 — SNLR
Weighting: 40%Definition
The SNLR (Sales-to-New-Listings Ratio) measures the instantaneous pressure of demand on supply. It is the central indicator used by the APCIQ and l'ACI to qualify a market.
Raw Calculation Formula
Conversion to 0-100 Sub-score
This conversion centers the value 50 on an SNLR of 40%, which corresponds to the threshold between a buyer's market and a balanced market according to industry standards.
Interpretation Thresholds
| Raw SNLR | Zone | Sub-score |
|---|---|---|
| Under 40% | Buyer's Market | 0 — 50 |
| 40% to 60% | Balanced Market | 50 — 80 |
| Over 60% | Seller's Market | 80 — 100 |
Why 40% Weighting
The SNLR receives the highest weighting because it is the only indicator that captures simultaneously supply and demand for the period. The other two components capture complementary but less synthetic signals.
Ventes : 404 · Nouvelles inscriptions : 822
SNLR = 404 ÷ 822 = 49,1 %
ScoreSNLR = 50 + (49,1 − 40) × 1,5 = 63,7
Component 2 — Expiration Ratio
Weighting: 30%Definition
The expiration ratio measures the proportion of listings that have expired or been withdrawn from the market without resulting in a sale. It is a signal of a(n) mismatch between asking prices and actual purchasing power.
Raw Calculation Formula
Conversion to 0-100 Sub-score
A low expiration ratio signals strong absorption of the market and receives a high score. A high ratio signals a price-market mismatch and receives a low score.
Why 30% Weighting
The expiration ratio captures a qualitative signal that SNLR alone does not reveal: the quality of matching between supply and demand. A market may show a balanced SNLR but a massive wave of expirations, which then reveals a price deadlock.
Ventes : 404 · Expirations : 399
Ratio = 399 ÷ (404 + 399) = 49,7 %
ScoreExpirations = 100 − (49,7 × 3,33) = 34,5
Component 3 — Annual Momentum
Weighting: 30%Definition
Annual momentum (year-over-year, or YoY) measures the variation in sales volume compared to the same period the previous year. It captures the cyclical dynamic of the market by eliminating the seasonality effect.
Raw Calculation Formula
Conversion to 0-100 Sub-score
This conversion corresponds: YoY −10% → score 0; YoY 0% → score 50; YoY +10% → score 100.
Why 30% Weighting
Annual momentum eliminates the natural seasonality of the real estate market (active spring, calm winter) and reveals underlying dynamics. It complements the SNLR (snapshot) by adding a temporal perspective.
Ventes 2026 : 404 · Ventes 2025 même semaine : 442
YoY = (404 − 442) ÷ 442 = −8,6 %
ScoreMomentum = 50 + (−0,086 × 500) = 7,0
Summary of the Complete Example
For the week of May 2-8, 2026, the Tardif Index is therefore:
= 25,5 + 10,3 + 2,1
= 37,9 / 100 → Zone Light buyer's
5. The Five Interpretation Zones
The overall Tardif Index score is interpreted according to five zones, calibrated against standard thresholds of the Quebec real estate industry.
| Score | Zone | Interpretation | Implications for Buyers | Implications for Sellers |
|---|---|---|---|---|
| 0 — 20 | Strong buyer's | Strong downward pressure on prices, high inventory, low sales volume | Maximum negotiation power, rare bidding wars, abundant choice | Difficulty selling at asking price, extended deadlines, frequent price adjustments |
| 21 — 40 | Light buyer's | Buyer negotiation power, moderate to high expiration ratios | Negotiation possible, strong financial file preferred | Realistic prices essential, impeccable presentation necessary |
| 41 — 60 | Balanced | Stable power balance, SNLR close to 50%, healthy market | Normal conditions, decisions to be made based on individual criteria | Reasonable deadlines, defensible prices consistent with comparables |
| 61 — 80 | Light seller's | Moderate upward pressure, occasional multiple offers | Responsiveness required, mortgage pre-approval essential | Favorable position, asking prices generally met or exceeded |
| 81 — 100 | Strong seller's | Frequent bidding wars, marked upward pressure, low inventory | Expected bidding wars, decisive financial file, sometimes requiring no financing conditions | Maximum leverage, asking prices regularly exceeded |
“Methodological transparency is not a competitive risk: it is what distinguishes a defensible analysis from a personal opinion.”
6. Data Sources
The Tardif Index relies exclusively on verifiable data accessible to professional real estate brokers.
Source System
All data comes from Centris (Multiple Listing Service), the official database for Quebec real estate brokers, operated by Centris.
Covered Territory
Island of Montreal exclusively, including the 19 boroughs and related cities. The North and South Shores, the South Shore, and Laval are not covered by the current Tardif Index.
Included Categories
- Condominium (condos)
- Single-family homes (detached, semi-detached, townhouses)
- Duplex
- Triplex
- 4-plex (quadruplex)
- Multi-unit 5+ (small income properties)
Excluded Categories
Transactions commercial, industrial, vacant land, farms, and chalets are excluded from the Tardif Index, which is strictly residential in scope.
7. Publication Frequency
| Type | Period Covered | Publication Day | Depth of Analysis |
|---|---|---|---|
| Weekly Bulletin | Previous Week (Monday-Sunday) | Every Friday | 800-1 200 mots |
| Monthly Edition | Previous Month | 2nd or 3rd of the following month | 3 500-7 000 mots |
8. Calibration and Cross-Validation
The Tardif Index is calibrated to industry standard thresholds and is regularly cross-validated with official publications.
Convergence with APCIQ Indicators
The thresholds used for the SNLR (40%, 60%) correspond to those published by APCIQ and ACI. For March 2026, APCIQ reported a monthly SNLR of 59% for the Island of Montreal: the Tardif Index for the weeks of March (excluding a one-off anomaly of expirations) ranged from 54-58, in the same interpretation zone as APCIQ.
Differences from Competing Indicators
The Tardif Index differs from official publications by:
- Its monthly cadence, supported by weekly bulletins (vs. quarterly for CMHC)
- Its synthesis into a single figure on 100 (vs. separate and nuanced indicators)
- Its focus exclusive to the Island of Montreal (vs. broader regional averages)
- Its fully public and reproducible methodology
9. Limitations and Usage Precautions
The Tardif Index is a synthetic indicator. Like any indicator, it has limitations that all users should be aware of.
- Volatility on small volumes. 4-plex and 5+ multi-unit categories record low weekly volumes (often fewer than 20 transactions). YoY variations may be amplified there and do not necessarily represent a fundamental trend.
- No individual prices. The Tardif Index reveals no sale prices, no addresses, and no identified brokers. It relies strictly on aggregates by residential category.
- Descriptive, not predictive, indicator. The Tardif Index describes market tension during the observed period. It does not predict future prices or market reversals.
- Delay of a few days for expirations. Expired listings are sometimes recorded in Centris with a delay of 1 to 3 days. Weekly bulletins incorporate an adjustment in the subsequent publication if necessary.
- Restricted geographical scope. The Tardif Index covers only the Island of Montreal. Dynamics of the South Shore, Laval, Vaudreuil, and other Greater Montreal regions are not reflected.
10. Methodology Revision History
| Date | Version | Modification |
|---|---|---|
| 1.0 | Initial Publication of Public Methodology |
Any future revision to the methodology will be documented in this table, with the exact date and nature of the modification. Editions published under version 1.0 remain unchanged.
11. Centris and OACIQ Compliance
The Tardif Index fully complies with the information dissemination rules issued by:
- Centris — no individual transaction data, no addresses, no information capable of identifying a specific property
- OACIQ (Quebec Real Estate Brokerage Self-Regulatory Organization) — compliance with real estate brokerage ethical rules
- Quebec Real Estate Brokerage Act
The Tardif Index does not constitute financial advice, a real estate investment recommendation, or a property appraisal. For these services, please consult a real estate broker or a certified appraiser.
12. How to Cite the Tardif Index
The Tardif Index is free for citation by media, researchers, professionals, and individuals. Source attribution is mandatory.
Suggested Citation Format
For the Media
Journalists wishing to cite the Tardif Index or request an exclusive analysis may contact David Tardif directly: