Set Rating Formula

theBobs

Does anyone have a spreadsheet or something that calculates the Set Rating? The reason I ask -- in my humble 65 set, I removed a single card (PSA 8 weighted 1.5) but added five cards (PSA 8, and four PSA 7's -- with the following weightings 1, 2, 1, 1, 1).

My set rating went from 0.64 to .60. Its really no big deal other than I'd like to understand the math behind the ratings.

Thanks

FB

Welcome to the club...

The other day after adding a bunch of new PSA 9's to me 72 set my rating was 8.48. The next day, I added one more PSA 9 to fill a hole and my set rating dropped to 8.34. There's a bug out there somewhere, but I figured that once I've completed the set if the rating didn't seem right I'd check into it.

Basilone

Brian,

I will email you a spreadsheet that I created for the 1965 set.

John

helionaut

First find the sum of all weights for the whole set. Then sum all your cards weights multiplied by their grades. Divide the first number into the second number, and you'll have your set rating. If the 1965 set has a weight sum of, say, 800, and your set has a grade*weight total of, say 480, your rating is 0.60. If you subtract 12 "points" for your 1.5-weight 8, and add another 43 points for your other 5 cards, your net gain is 31. So your new total will be 511. 511/800=0.64. Your sums were probably off because the set rating calculations aren't instantaneous, but it should go up in the end.

Wayne8348

There is one thing I don't like about the set rating formual (and believe me when I say that I don't have a better solution) is that low graded cards are given too much weight. My example is:

Say you have a Psa 10 card of a star with a weight of 5. This card may cost $500 to $2500 depending on the year and who it is. Another collector could have 10 psa 5's of common players with a rating of 1. The psa 5's may have a value of $5 apiece (if that) if they are less than 40 years old. Anyways, in this example each person would add 50 points to their overall set points which is to be divided by the total points in the set to see what is added to the set rating.

Long story short, the $500 to $2500 investment will have the same net result as the $50 or less investment in the low quality cards. I like the system of weighting the cards a lot but I'm not sure how equitable it is to give a 9 only 9 points while a 7 gets seven points given the huge disparity in values. But in theory a complete set of psa 5's would have the same total set value per the registry as a 50% complete set of psa 10's. Which would you rather have? If you say the complete set of 5's I will gladly assemble such a set and trade you for your 50% complete set of 10's.

Any thoughts?

Wayne

Vargha

Wayne -- I say not to worry about the ratings and collect the cards you want in the manner which is most effective for you. Although the Set Registry can appeal to one's ego, don't let that dictate your set building practices.

Wayne8348

Vargha,

I understand what you're saying and I really don't feel like it has any influence at all on how I collect. But if there is a more equitable way of doing it then why not try it? That's all I meant by the last post.

Wayne

Looking for perfection in an imperfect world.

HalleyGator

Because, Wayne, if you propose something reasonable like "weighting a card based on its market price"...

then many of the "do gooders" on this page will chastise you for worrying about the cost of your collection rather than the "esoteric value" of each card.

In other words... your proposal makes TOO MUCH sense.

Vargha

Although Hal, the problem is, what grade do you weight relative value at? And do you do it at SMR or prevailing market price (if it can be determined)? The system is fine. I could really care less that my 1951 Bowman #289 Cliff Mapes sells for $3,000+ in PSA 8 and has a value of 2.5 while #165 Ted Williams sells for $2,300 in PSA 8 and has a value of 7.0. I just don't make my purchases based upon the Registry.

bosoxphan

There would be an unbelievable amount of change in the weightings from month to month if they were tied to market prices. It'd be a nightmare for newer sets, since the population numbers can change dramatically. Guess it depends on whether you want set weightings or fluid weightings.

Wayne8348

I didn't mean to tie it to market value. I just meant to give more value to higher rated cards than a single point on a 8 vs a 9. Many times the cost is double or more yet the reward on the registry is only a 11% bonus vs. the lower graded card. Two 5's shouldn't equal a 10. What if the points worked something like this:

10 = 20 points
9 = 15 points
8 = 10 points
7 = 7 points and then so on.

There truly is approximately a 1 point difference between a 6 and a 7 but that can't be said between a 9 and a 10. All something like this would do is give a more accurate reflection of the overall quality of the set. This would actually hurt me because my set is straight 8's but it would be more accurate. What do you think?

Wayne

purelyPSA

A couple of things.

First...just my two cents, but really, the set ratings are not that important at all, as far as resale value of a particular collection goes. Unless you are trying to sell a really fantastic set whole (the "pedigree"), exactly where you fall on the registry of any particular set is not that consequential. If you diligently assemble a quality set, it will be recognized as such, whether you're 1st or 10th overall. Take a look at the gaggle of 1972 Topps groupies - all are well respected. If each came forward with their collections to sell, they'd all draw all kinds of bids - it wouldn't matter if that particular person happened to be first on the Registry or fifth. Really, the registry is just a way we can all keep score, as well as a convenient way to stroke our own egos (and fatten the bottom line for PSA).

As far as adjusting point values to reflect the quality of a grade rather than the quality of a player - that's a really slippery slope. I'd hate to see a set loaded with PSA 10 commons and crappy stars thump someone with a much stronger collection from a particular year. Plus, this would drive the value of 10's through the roof, which I don't think reflects well on collecting: it says to me, get 10s or get stomped. I think that's the wrong message to send.

Wayne8348

First...just my two cents, but really, the set ratings are not that important at all, as far as resale value of a particular collection goes.

I never suggested that it was. The market dictates resale - not set ratings. All set ratings do is compare one set to another. I'm just suggesting that it can be done more accurately.


As far as adjusting point values to reflect the quality of a grade rather than the quality of a player - that's a really slippery slope. I'd hate to see a set loaded with PSA 10 commons and crappy stars thump someone with a much stronger collection from a particular year. Plus, this would drive the value of 10's through the roof, which I don't think reflects well on collecting: it says to me, get 10s or get stomped. I think that's the wrong message to send. >>



I have no clue as to what you mean by this. I set loaded with psa 10 commons is a strong set!!! It's not all about buying to big dollar star players in high grade. The stars are already being given a higher weight (on most sets anyways). It wouldn't be as drastic of a change as you might think. Afterall 4 psa 5's would still equal 1 psa 10. It still wouldn't be perfect - just more accurate. Forget resale, I never brought it up, forget stars vs commons, they're are already weighted, just prove to me that a set of 50 psa 5 common cards from 1965 is a better collection than 24 psa 10 common cards from 1965. The first example is worth 250 points as compared to 240 points from the last example. If the 50 psa 5's represent a better collection then I have mud all over my face and I'm completely wrong. If not, then why not try and adjust it to make it somewhat more accurate (understanding that it will never be perfect in all situations).

Wayne

Wayne8348

I just got out of the shower and that's where I do my best thinking so I'm going to take 1 more stab at this before I leave town for the weekend. Let's assume that a psa 9 of the exact same card will sell for approximately double to triple a psa 8 and I realize there are many examples contrary to this.

Registry

psa 8 x 1.11 = psa 9 registry value
psa 9 x 1.11 = psa 10 registry value

Market

psa 8 x 2 = psa 9 market value
psa 9 x 4 = psa 10 market value

Proposed

psa 8 x 1.5 = psa 9 registry value
psa 9 x 1.33 = psa 10 registry value

You see - the proposal would still be far under what the actual swings in the market are. It would give just slightly more weight to these cards and hopefully give a better representation of how the sets compare.

Wayne