Analyzing Coin Value Data to Determine Intermediate Values

Discussion in 'Coin Chat' started by kanga, Nov 25, 2020.

  1. kanga

    kanga 65 Year Collector Supporter

    I spend a fair amount of time trying to determine how much to pay for or to bid on a coin.
    Particularly tough is when there are no reported prices for a certain grade.
    For instance, what if you can find several results for VF-30 and XF-40 but you are looking at a VF-35.
    I know it's not linear, i.e., the average (50%) between VF-30 and XF-40 prices will be a bit high for VF-35.
    It probably should be more like 40% of the difference.
    I'd like to pin down that percentage more accurately.

    Unfortunately I know just enough math to get ideas on how to determine that.
    And thanks to Excel I can try my ideas out.
    But is my math on solid enough ground to put my money where my ideas tell me to go?
    Only testing will tell me.

    And of course a math analysis cannot take into account your desire for the coin or its eye appeal.
    But maybe it's a starting point.

    Anyone get that deep into determining a price?
    Or do I have too much time on my hands because of COVID o_O
  2. Avatar

    Guest User Guest

    to hide this ad.
  3. CoinCorgi

    CoinCorgi Derp, derp, derp!

    I vote too much time. Close enough for me is anywhere from 40% to 60% of the difference if the grade is half way between.
  4. Inspector43

    Inspector43 72 Year Collector

    Do you like the coin?
    Does it have good eye appeal?
    Are you buying for long term?
    Or, are you planning to flip it?
    I wouldn't worry about the spread between grades if I wanted it in my collection.
    jamor1960 likes this.
  5. Collecting Nut

    Collecting Nut Borderline Hoarder

    The price between two grades is not important to me. The appeal of the coin and how it fits into my collection are the main factors.
    micbraun and Inspector43 like this.
  6. physics-fan3.14

    physics-fan3.14 You got any more of them.... prooflikes?

    If you can't find a reasonable amount of past sales for the intermediate grade, I usually use about a third of the interval. I usually use the same for a + grade, as well.

    So, if 30 is worth $1000, 40 is worth $2000.... I'd generally value a 35 at $1300 or so. It's an approximation, of course.

    Well, when you're talking about large price jumps, the price can be quite important. Just to give you an example from my own collection:

    A 40 is valued at $7,000
    A 50 is valued at $11,000

    What value would you place on a 45?
  7. ToughCOINS

    ToughCOINS Dealer Member Moderator

    Long ago, before I began dealing in earnest, I similarly attempted to quantify intermediate grades mathematically.

    If the low, high and intermediate coins are all of the same quality for their respective grades, I suppose what you propose may make some sense.

    The formula I came up with those many years ago follows:


    Where INT lies exactly midway between LOW and HIGH.
  8. physics-fan3.14

    physics-fan3.14 You got any more of them.... prooflikes?

    Interesting. Do you still use this same formula, or have your methods evolved?

    In my example above, your formula would give me $8775, my 33% rule would give me $8333, and kanga's 40% idea would be $8600.

    Your formula seems a bit high, but it might apply to some issues.
  9. Collecting Nut

    Collecting Nut Borderline Hoarder

    It all depends on the coin in question, it's appeal to me and how it fits into my collection.

    I was at a show 2 years ago. I only need 2 coins to complete my collection. The value on these is around $650 each. I've been looking for about 5 years for these 2 coins. At this show the same dealer had both coins that fit my needs.

    I inquired about the price and he wanted $950 for one of them and $900 for the other. He said if I bought both he could do $1750. I thanked him and walked away.

    About 20 minutes later I made it to another table and the dealer was very nice. He confirmed the price of each at the $600-$650 price range. He didn't have either of the coins I needed but I did buy a sweet PCGS Bust Half from him at a very good price.

    I'll overpay if it's what I want and meets my needs but I'll not be ripped off.
  10. ToughCOINS

    ToughCOINS Dealer Member Moderator

    Admittedly, it does look high. I don't recall if it fell more in line with published pricing for intermediate grades all those years ago, but I believe it must have, or I might have spent more time refining the formula.

    Honestly, I don't have any "rule" that I follow. I've developed pricing instincts based on market observations and what I've seen and, just as importantly, not seen.
  11. KSorbo

    KSorbo Well-Known Member

    In my experience the AU58 grade is the intermediate grade with the biggest jump in price. Much more than 30 to 35 or 50 to 53 or 55.
  12. micbraun

    micbraun coindiccted

    This. If you’re not flipping the coin I don’t think it really matters.
  13. physics-fan3.14

    physics-fan3.14 You got any more of them.... prooflikes?

    If you're talking $20 between grades, then what's a fiver between friends?

    If you're talking a few thousand dollars between grades, I darn well better be sure I'm paying the right price.
  14. physics-fan3.14

    physics-fan3.14 You got any more of them.... prooflikes?

    I often find, personally, the jump from 58 to 60 has a huge jump up in price, but often a step down in quality. Take a look at this price graph for a 1955 DDO Lincoln... very slight growth through most circulated grades; big jump at 60, and exponential after that.

    If we're looking at VF-20 vs 25 vs 30.... not much difference at all. Not worth spending much time here. If we're looking at the difference between 63 and 63+.... big difference.

    micbraun likes this.
  15. micbraun

    micbraun coindiccted

    Agreed. But even then I would not rely on a formula, but ask myself if the price difference is acceptable ?
  16. physics-fan3.14

    physics-fan3.14 You got any more of them.... prooflikes?

    I think the heart of this thread is - how do you determine the answer to that question? What's acceptable to you?
  17. ddddd

    ddddd Member

    If quality is similar (all solid for the grade), then I can see using 40%-50% of the difference. Now if the coin looks weaker (but you still wanted it), I would adjust that down to something smaller (say 20%). And if the coin has great eye appeal, don't be surprised if it goes for close (or even more) than the next grade level.
  18. micbraun

    micbraun coindiccted

    Depending on the coin’s condition, variety, rarity level and/or collectors interest of the series it could be anywhere between the two grades or even above the next higher grade. Even if we ignore types/varieties, CAC stickers, slab generation (fatty/rattler), etc. there’s not a single answer to this question.
    Last edited: Nov 26, 2020
  19. LRC-Tom

    LRC-Tom Been around the block...

    Since I buy for resale, I have to think about how my potential buyers will do their evaluations. And I have found over the years that many people will pay more attention to the letter grade than they do to the numerical grade. In other words, they focus more on the "VF" and not so much on the "30". So I tend to pay no more than 20%-30% more for an intermediate grade, unless the coin is especially appealing. You're a collector, though, so this evaluation method really doesn't apply. As others had said, buy what you like.
Draft saved Draft deleted

Share This Page