Posted By:
Eric BrehmI have found the Sports Market Report to be reasonably accurate for valuation of cards in the 1933 Goudey set, which I have been working on for about a year. It gets you in the ballpark. Of course prices vary for all cards depending upon the strength of the card within its assigned grade and other factors, so the SMR value is only a guide, only an average.
The one exception to the above is some of the scarcer 1933 Goudey common cards, which come up for sale infrequently, and thus are hard to estimate market values for. Also the prices realized for these cards in auctions tend to vary widely depending on who happens to need them for their set, and how motivated they are to compete for them. If there are two or more people who decide to go head to head on it, the sky's the limit. Example: recent prices realized in major auctions for #27 George Connally in PSA 8 that I am aware of include: $7589 (2004), $2637 (2005), $1160 (2006), and $2911 (2006). An auction tracking service is helpful in these cases, to see some of the recent auction results, and at least get a range of expectation.
I would also point out that the SMR tends to be self-fulfilling prophecy to some degree, since many people do use it as a guide, or reference point, for deciding how much they are willing to pay for a particular card. In other words, the very act of using the information in SMR for buying decisions tends to reinforce the validity of the information itself.