Its in the book, the explanations of how they make their decisions.

Quoted from Monkeybug

Its in the book, the explanations of how they make their decisions.

More specifically, Appendix D.

From the Mr. Pinball price guide, page 124:

Quoted Text

How Values Were Determined
We used thousands and thousands of data points from many sources, primarily list prices, known sale prices, offers to buy, and auctions prices for the past year. We go through the data manually and adjust for currency exchange rates and condition, and throw out any obvious bogus data. Then we run the data through a statistical analysis and computer mean, standard deviation, error rates, etc. Then we throw out the high and low data points and do it again. This gives some numbers as a starting point for comparison.

Then we manually go through each of these results and compare against last year's value, and using our knowledge of the machine and the market, we make a judgment call, selecting a value which may be the same, different (higher or lower). This is not the end.

Then we go through again normalizing the values by looking at machines grouped chronologically by manufacturer and compare like machines and see if anything looks out of place and make adjustments here and there. Usually these are smaller adjustments.

Yes, it's tedious.

The guide is just a guide. I find most of the values to be spot on, while others are obviously a little off. For the most part, however, I think it does a good job of reflecting a pin's real value.

As for who determines the value of a machine, I'd say it's a community like RGP or maaca and the open marketplaces like mrpinball.com, ebay and live auction results that do the most to determine value. I really don't think that Daina Petit (the Price Guide author) and his friends sit around and haphazardly pull numbers out of the air to determine the values of pinball machines. If that was the case, the price guide would be a joke and collectors would never buy it. I mean, imagine if Daina printed in the book that Hollywood Heat is worth $3,500 and Cactus Canyon is worth $500. Do you think that would be a legitimate valuation of those games? I don't. And I don't imagine many other people 'in the know' would either.

If the values printed in the guide reflect, as accurately as possible, what the general pinball collector community believes to be reasonable, then the guide is doing its job. And with that in mind, therefore, it's the collector community that determines the values, not a handful of individuals. Make sense?