Real estate data is simultaneously more abundant and more confusing than at any point in history. Every month, Markham buyers and sellers are confronted with multiple competing statistics — year-over-year declines, five-year gains, month-over-month changes, benchmark versus average price, sold price versus list price — and the numbers frequently contradict each other in ways that make coherent decision-making feel impossible.

Michael John Lau, top real estate agent in Markham Ontario and a CPA/CMA, spends a meaningful portion of every buyer and seller conversation on data literacy. The question of which number to care about is not academic — it determines whether you make a sound decision or an emotionally reactive one.

The Two Numbers and What They Actually Measure

The 10.41% year-over-year decline measures the difference between what Markham homes are selling for today versus what they were selling for twelve months ago — capturing the correction from 2024–2025 pricing that was itself elevated relative to longer-term trend. The 9.36% five-year gain measures where Markham sits relative to mid-pandemic prices in June 2021 — and it is still positive, even after absorbing today’s correction. Neither number tells you what the market will do in the next twelve months.

The Number That Actually Matters for Each Buyer and Seller

If you are a buyer making a purchase decision today with a seven-to-ten-year holding intention: care primarily about the ten-year trend (45.77% appreciation) as the baseline for long-term expectations. Use the five-year trend (9.36% gain from corrected levels) as context for medium-term positioning. Use the benchmark decline (-6.7%) as negotiating context for today’s offer pricing. The one-year average decline (-10.41%) is the least useful number for a long-term buyer because it captures a correction that is already in the rearview mirror of any purchase made today.

If you are a seller pricing your home: the one-year trend is the most relevant context, because it reflects what buyers have been trained to expect by recent comparable sales. Buyers who have been tracking the market for twelve months know comparable homes have been selling 10% less than a year ago — your pricing strategy must account for this.

If you are an investor: the ten-year number is the most relevant. At 45.77% over ten years — approximately 3.8% per year in average annual price appreciation — through multiple interest rate cycles, government policy interventions, pandemic distortions, and a significant correction — Markham has delivered consistent long-term value.

The Benchmark Price vs. Average Price Distinction

One additional data literacy point every Markham buyer and seller should understand: the average price and the benchmark price measure different things and frequently diverge.

The average price is the arithmetic mean of all sold prices — highly sensitive to the mix of property types transacting. When more condos sell in a given month relative to detached homes, the average falls for compositional reasons even if individual property values have not changed.

The MLS HPI Composite benchmark price was down 6.7% year-over-year in May 2026 at $946,500. The benchmark measures the value of a “typical” home, controlling for property type mix shifts so that like is compared to like.