Pinball prices vs. IPDB rank: graph. UPDATE: now with Pinside rank

(Topic ID: 76544)

Pinball prices vs. IPDB rank: graph. UPDATE: now with Pinside rank


By nosro

4 years ago



Topic Stats

  • 36 posts
  • 22 Pinsiders participating
  • Latest reply 4 years ago by Hammerhead
  • Topic is favorited by 4 Pinsiders

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    chart2.png
    values.png
    chart1.png

    #1 4 years ago

    I may have to put on my flame suit, but my inner statistician has wondered about this. The correlation isn't awesome (R squared is 0.17), but it is definitely not a meatball, either. I hope no one takes this too seriously - I don't.

    I used the year-to-date average transaction price from the latest bostonpinball.biz Ebay prices and the IPDB rank as of yesterday. There are some problems that I noted. Some problems include:
    1) Differences in ranking between LE and standard edition machines. In some cases, the LE ranked worse than the standard edition. Meanwhile, the Boston Pinball survey in some cases did not differentiate between LE and standard.
    2) Some machines had a price sample size of one or no data was available. In cases where no data was available, I left the data out - the difference between 2013 prices and the long term (before "pinflation") data is just too large in most cases.

    This kind of data obviously does not take into account many factors. Some things I can think of that make this type of correlation suspect:
    1) The prices have not been adjusted for condition. Highly coveted titles with very good IPDB rankings are probably in better condition than less coveted titles, on average.
    2) Hard-to-find machines (such as Safe Cracker or Cactus Canyon), which necessarily have higher prices, ranked consistently low on IPDB. Both the higher prices and low rankings are probably just artifacts of low quantities and would tend to throw off this correlation.
    3) The data do not reflect each individual transaction. Therefore, a single data point may be 1 machine or 20 machines. That is a problem since, ideally, there would be 20 data points if a title actually had 20 transactions. This results in machines will fewer transactions having undue influence on the correlation compared to titles with more transactions.
    4) The fit is definitely much higher than reality. The few titles fetching extraordinarily high prices move the best fit line up badly. (I would love to be able to sell my Judge Dredd for $5000, according to the best fit line.) As I noted, please don't take this too seriously.

    Here is what I found interesting. I would have thought that prices would start flattening at around rank 50 or so, but the prices seem to continue declining within the top 100. Obviously it has to flatten out at some point, but it is not before 100.

    chart1.png

    UPDATE 1/10/14: I redid the correlation but against Pinside rankings. The some caveats apply, but the correlation is much better. R squared is 0.45 which most statisticians would accept as a good correlation.

    One thing I noticed is that Pinside rankings are more up to date with the latest Stern machines and that IPDB tends to have somewhat older reviews. That may have something to do with IPDB rankings being somewhat better for older machines than Pinside rankings that seem to heavily favor DMD machines.

    chart2.png

    UPDATE 1/20/14:

    c3.png

    c4.png

    The distinction between Stern and Williams machines appears to be noteworthy. The Stern machines seem to have little correlation - the prices are all within a band regardless of rank. Also, if only Williams machines are considered (remove Stern data points), prices start to level out at approximately rank #25.

    #2 4 years ago

    Interesting.

    Would be nice to control for production numbers and regional location of sales

    #3 4 years ago
    Quoted from 27dnast:

    Interesting.
    Would be nice to control for production numbers and regional location of sales

    Agreed. The Boston Pinball data is very limited. Garbage in, garbage out.

    I think there is still something useful here - like identifying the machines on the bottom side of the cloud as "high value" machines.

    #4 4 years ago

    Where's the multiple regression?

    #5 4 years ago

    How does the Boston Pinball data take into account sales where best offer was accepted? I don't believe you can view those - it just shows the asking price crossed out.

    #6 4 years ago

    Interesting plot, thanks.

    Robert

    #7 4 years ago

    I was told there would be no math.

    #8 4 years ago

    Does adding error bars help? I'd assume poissonian noise on the sale prices (error = √N) and maybe on the rankings too. Also, why not regress against rating rather than ranking, again with an error estimate?

    Quoted from Shadow_E:

    I was told there would be no math.

    If that's what you got from this thread title....

    Some of us actively enjoy math, dude

    #9 4 years ago

    What is that game in the lower right hand corner? Maybe add a table

    #10 4 years ago
    Quoted from PinballTilt:

    What is that game in the lower right hand corner? Maybe add a table

    Looks like Blackout?

    #11 4 years ago

    For those that are as curious as I was, here's which titles line up with the best values according to the graph. Numbers don't lie!

    values.png

    #12 4 years ago
    Quoted from supercombo:

    For those that are as curious as I was, here's which titles line up with the best values according to the graph. Numbers don't lie!

    values.png 65 KB

    Judge Dredd is #49. You must have that mislabeled

    #13 4 years ago

    Forget that ignorant response.... just read "IPDB RANK"... looked on pinside.

    Thanks for doing that!

    #14 4 years ago
    Quoted from 27dnast:

    Forget that ignorant response.... just read "IPDB RANK"... looked on pinside.
    Thanks for doing that!

    Hah! No worries. The ratings here on Pinside vs. IPDB are significantly different, although the overall number of people rating here seems much higher than IPDB. Might be interesting to do the same comparison using the Pinside Top 100. Up for the task, nosro?

    #15 4 years ago
    Quoted from supercombo:

    Numbers don't lie!

    But liars do numbers..

    P.s. Not suggesting you're a liar.. just questioning the wisdom of taking numbers provided by others at face value.
    The road it hell is paved with pretty graphs..

    #16 4 years ago
    Quoted from swf127:

    But liars do numbers..

    Very true! I was being glib, because the truth is that there's never a monetary value that universally conveys the appeal of a pinball machine. Everyone has their favorite machines and different measures of fun, and they may be cheap or they may be supremely overvalued by someone else's measure.

    #17 4 years ago
    Quoted from supercombo:

    Up for the task, nosro?

    Done. Updated the first post with the chart for Pinside rankings. The prices correlate with Pinside rankings much better and probably as well as it could ever get due to the lack of detail in the Ebay prices.

    That better correlation was a bit of a surprise for me. If nothing else, it suggests that Pinside rankings are a better representation of the community's overall impression of a machine.

    #18 4 years ago
    Quoted from swf127:

    But liars do numbers..
    P.s. Not suggesting you're a liar.. just questioning the wisdom of taking numbers provided by others at face value.
    The road it hell is paved with pretty graphs..

    As I was getting a bank loan for my business many years ago, my Father quips up 'figures don't lie, but liars figure' I'm like dad, WTF. I'm trying to get a loan here. LOL

    #19 4 years ago
    Quoted from nosro:

    Done. Updated the first post with the chart for Pinside rankings. The prices correlate with Pinside rankings much better and probably as well as it could ever get due to the lack of detail in the Ebay prices.
    That better correlation was a bit of a surprise for me. If nothing else, it suggests that Pinside rankings are a better representation of the community's overall impression of a machine.

    Too bad you did not have accurate and pertinent data to work with. I would have loved to see the end result. But, most of pinball sales are private cash deals and not at public auctions or ebay.

    Very cool non the less.

    #20 4 years ago

    Nosro,

    nice work! Love to see data represented well in an easy-to-see format. Might I make a couple of comments/suggestions on ideas for display?

    Taking your Pinside chart as the basis;

    1) Have a chart that color codes the dots by decade (green for 80's, blue for 90's, etc). Be interesting to see differences in era.

    2) Have the chart have different colors for manufacturers (B/W vs. Stern/Sega/DE).

    3) Like supercombo did, have some arrows and text pointing out the names of the largest outliers. #1 at $13K is obviously MM. What's #26 and #27? What's #81?

    Thanks,
    EV

    #21 4 years ago

    Good ideas, EV. I'll work on that.

    #22 4 years ago

    What are the machines towards the other end of the spectrum....which titles have high prices but low ratings?

    #23 4 years ago

    I will work on labeling the ones on the low end and on the high end.

    #24 4 years ago

    Getting those dots labeled would be awesome.

    As most of us already knew....it's the higher ranked but still around 2k 90's pins (with some classic 80's sprinkled in) that offer the best "Bang for your Buck".

    #25 4 years ago

    ...

    #26 4 years ago

    I enjoy a good chart! Thanks for making a pinball related one. Nice work

    #27 4 years ago
    Quoted from nosro:

    I may have to put on my flame suit, but my inner statistician has wondered about this.

    I think you will sometimes find that the people that complain the most about something here, are the ones that usually don't do much other than criticize.

    Again, nice charting.

    Robert

    PS: I think your "fit" line should probably be logarithmic or power rather than linear.

    1 week later
    #28 4 years ago

    Updated first post with chart sorting data points by decade and by manufacturer.

    1 week later
    #29 4 years ago

    Looks great thanks for the info

    #30 4 years ago

    I played connect the dots with those graphs and it turned into a MMR

    #31 4 years ago

    This is a great idea. One of my current "confusions" (I have many....lol) is why an X-MEN LE with better reviews and a pinside ranking consistently in the 30's (has stabilized for awhile now) is selling for around $5K-$5.2K and why a HULK AVLE (which has rankings in the 80's now and still dropping) sells for more. Can't understand that one but the main reason I held off buying a HULK LE a few months ago (prices were in the $6ish range but have come down some) because I figured eventually the HULK LE would sell for the price of the X-MEN LE or even less (since people seem to prefer the X-MEN LE).

    Sometimes the pricing doesn't always "seem to make sense" but many times they correct over time. Personally, I rarely buy a game that is a "dog" as I find they are harder to get rid of when you decide to turn over your collection for some other pins (again why I am probably crazy to even want a HULK LE.....before I know it the game will be ranked in the 100's the way it keeps dropping).

    GREAT JOB as I truly try to use the rankings to help justify purchases to "some degree". However, some games (IM comes to mind) weren't popular when they were made (so production got stopped early) and then became popular later so you have to take into account limited supply as well (IM only had 1,100 made I have been told).

    Some games WW and HS2 always seemed like great values as well as BSD (I own BSD and HS2 and paid less then $3,500 for both and they are great games).

    THANKS FOR DOING THIS !!!!! Brings me back to my statistics class many years ago.

    #32 4 years ago

    fun stuff

    #33 4 years ago

    Ray, pretend for a moment that I don't know anything about metallurgy, engineering, or physics, and just tell me what the hell is going on.

    #34 4 years ago
    Quoted from DarkWizard:

    Ray, pretend for a moment that I don't know anything about metallurgy, engineering, or physics, and just tell me what the hell is going on.

    You never studied.

    #35 4 years ago

    Damn man , how do you do in the stock market?

    6 months later
    #36 4 years ago

    My brain hurts

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