According to some sources the Victorian property market clearance rate was as high as 81% on the weekend or as low as 65%.

How can we have such variance over numbers that should be factual?
 
Below I have included two sets of numbers from two different data sources.
 
Data Set 1
 
Based on 1295 Auctions
Sold at auction
565
Sold prior to auction
258
Sold after auction
17
Withdrawn
174
Passed in
281
 
Data Set 2
 
Scheduled Auctions
1401
Reported Auctions
776
Total Sold
627
Total Passed In
149
Clearance Rate
81%

The variation in Melbourne’s auction clearance rate reporting comes down to several key factors:
Data Sources – Different real estate agencies and analytics firms (such as CoreLogic, Domain, and REIV) collect and interpret data differently. They may have different methodologies, cut-off times, or ways of handling missing results.
Timing of Reporting – Early reports (typically on Saturday or Sunday) are based on preliminary data, which can change as more auction results come in. Clearance rates often decline as additional unsuccessful auction results are reported.
Withdrawn or Unreported Auctions – Some agencies may exclude withdrawn auctions or those with undisclosed results, making their reported clearance rate appear higher. Others attempt to estimate outcomes for unreported auctions, which can introduce variations.
Definitions of ‘Sold’ – Some reports count only properties sold under the hammer, while others include post-auction negotiations. The latter approach generally results in a higher clearance rate.
Seasonality & Market Conditions – Clearance rates can be affected by external factors such as public holidays, school holidays, interest rate changes, and overall market sentiment. Different sources may adjust for these factors in different ways.