So-called average prices aren’t a good gauge of what’s really going on in the real-estate market, according to a new report.

In “Averages & Anecdotes: Deciphering Trends in Real Estate Prices, Part I”, the Vancouver-based think-tank Urban Futures demonstrates how the most expensive sales prices skew data on how much most people are really paying, well, on average.

For example, the average price of a detached home in the Lower Mainland in 2010 was $810,398, and that is taking into account the prices of all such houses sold that year. It shows that average prices increased 15 percent compared to 2009.

However, according to the study, median sales prices increased more slowly during that same period by 11 percent from $575,000 to $640,000. Median prices are the midpoint where an equal number of sales were made above and below this figure.

“The difference between changes in the average price and the median price is a simple indicator of how skewed the underlying data are,” the paper states.

The discrepancy is evident if the top 20 percent of sales by value or price for detached homes in Metro Vancouver was taken out of the equation. The average price of the remaining 80 percent of sales was only $591,092. The paper notes that this is 27 percent below the average price if the most expensive sales were included.

The same outcome can be seen in the condo and apartment market. There were 21,451 condos and apartments sold in the region in 2010. Although the volume fell 24 percent compared to 2009, average prices in 2010 rose 12 percent to $429,764.

However, the Urban Futures report notes that prices in the top 20 percent of sales by value in this particular segment of the real-estate market increased more than six times the rate in the bottom 80 percent.

“This resulted in a 2010 average sales price for the top quintile of $904,338, while the average sales price for the remaining 80 percent was only $311,069,” the paper states.