
Can I Use Data to Beat Christie's Auction Estimates? - Artnome
https://www.artnome.com/news/2017/7/27/can-i-use-data-to-beat-christies-auction-estimates
======
owenversteeg
Honestly, I think Christie's has an interest in their estimates being semi-
accurate, but not _too_ accurate. They obviously want to be within an order of
magnitude so they don't look stupid, but overestimating might drive up the
price and make them money. Also, when things sell for double or triple the
estimate, it makes the news, with Christie's name right beside.

Someone else said Sotheby's bought a database of art prices for 7 figures -
why wouldn't a bunch of headlines with their name be worth a few million to
them?

Additionally I think they have an interest in prices being as high as possible
normally, with estimates high to encourage that. So the pattern would look
like:

Antique Japanese woodcarving, $10MM predicted -> $12MM public predicted

Set of documents from Roman times, $5MM predicted -> $6MM public predicted

Van Gogh paintings (aka more headline potential), $10MM predicted -> $3MM
public predicted

Then you get the headlines "Van Gogh paintings fetch more than triple the
estimate at Christie's auction", which is free PR for Christie's.

------
kolbe
If you cannot, I would be shocked. Price estimates at auction houses are not
their best faith effort at estimating sales prices. They are much more
complex, and involve to some degree, an attempt to manipulate the price as
high as possible.

------
jaclaz
I wonder what is the point.

It seems to me like a back-justification of something not measurable
analitically.

A 5 millions US$ bracket is not in any way an approximation.

IF you had narrowed the interval (and IF the picture is at the auction sold
within it), then all your data mingling exercises might have some usefulness,
otherwise it is just an arbitrary estimation like the one from Christie's.

So the similarity calculated by an arbitrarily chosen software between (photos
of) study and painting of improvisation #8 is 64%.

The similarity between (photos of) study and painting of improvisation #20 is
a MUCH lower 57%.

It is clear how this HUGE 7% different can easily bring down the value of the
estimation by more than 50% from the improvisation #8 sale price of 23
millions for a 98x70=6,860 sqcm painting, i.e. 3,350 US$/sqcm to a mere 10
millions for the improvisation #20, a 71x99=7,029 sqcm painting, i.e. 1,423
US$/sqcm, give or take a couple of millions.

~~~
Artnome
Thanks for reading, I hope to improve the analysis over time. I spent the last
three years building a unique database that contains the complete paintings of
~40 of the best known artists of the twentieth century. I was motivated by
reading about the large percentage of works that are forged or misattributed.
I had always just assumed there was a single database listing how many works
artists created, average size of the works, changes in materials over time
etc. (similar to sports stats). After asking around and learning no such
database exists I decided to build one. Getting my blog out there has allowed
me to meet with a lot of really sharp folks like yourself who are helping me
refine the analysis.

~~~
jaclaz
>Thanks for reading, I hope to improve the analysis over time.

Good, but I don't see the analysis at all.

I mean you are betting (without any actual money which is good) on the actual
auction price of something in the future.

The auction price of a work of art - by definition - is not in any way like
the actual market value of anything (it will be MUCH lower or MUCH higher or
JUST ABOUT right) depending on a zillion factors that have nothing to do with
the actual value of the piece.

And you have so few data points that a statistical approach is mostly
meaningless, let alone one based (in the case of a study) based on the
differences between it and the final painting.

You could use a few sessions of flippism and get a similar value.

Or count the number of unique RGB colours in the (photos of) the paintings and
give each one a value between 1,217 and 23,146 US$ depending on brightness ,
later multiplied by the square root of the year it was painted and arrive to a
same "mathematical" estimation.

------
ata6187
Not sure what you're exactly building here, is it for fun or profit or both?

I heard when Sotheby's bought the Mei Moses Database/Index last year, the
valuation they paid for it was in the 7 figures. This type of data analysis is
on people's minds more and more and potentially quite lucrative, good luck.

~~~
Artnome
Thanks for reading my post. I am building a database of complete known works
across the most important art and artists of the twentieth century. Currently
no such database exists. Hoping to work with folks much sharper than I am to
build out meaningful analytics around art and artists using this new data.

~~~
audiometry
How do you collect the data for this??? Wondering how you measure your
completeness, for instance.

------
warrenm
They have the same data available ... seems like it'd be more like the
variations in weather models

------
orta
This is really cool work - if you're ever in New York City and want to chat
Art/Tech come by the Artsy offices (
[https://github.com/artsy/meta/blob/master/meta/happy_hour.md](https://github.com/artsy/meta/blob/master/meta/happy_hour.md)
)

~~~
Artnome
I'm a huge fan of Artsy, would love to chat some time.

------
muglug
Artnet has been doing the same basic analysis (finding comparable artworks and
calculating the worth of a piece of art) for over a decade. They offer theirs
as an add-on to their price subscription service:
[https://www.artnet.com/analytics-reports/](https://www.artnet.com/analytics-
reports/)

~~~
Artnome
Thanks for reading, Artnet is awesome. To my knowledge they do not have a
database looking at all known works by artists, they focus on works sold at
auction. This makes sense as they cover much larger group of artists and info
on complete works is typically not available for the majority of artists.

~~~
muglug
Yes – I think the point of sticking just to open auctions is so that the
prices and indexes they have represent what the market thinks of an artist and
particular works.

------
mholzap
This is awesome - really eye opening. This seems like a good proof point of
the inefficiency of the art market (partially due to lots of missing data,
partially due to the relatively small sample size of high-end art sales).
Excited to see where this goes, and how it impacts the efficiency of the
market.

~~~
garethsprice
Part of the art market's appeal is it's opacity, though - there's plenty of
manipulation that would be outright illegal in regulated markets, and plenty
of dirty money being washed through it - all contributing to the exploding
valuations for fine art in recent decades. I wonder how much transparency and
efficiency the art world actually wants, and what is the optimal amount to
maximize art valuations.

------
notwhiteknight
What about guarantees? That is a large component of auction price estimates. A
lot of these big name paintings are sold with the house guaranteeing a price
to the seller. Can't have a full understanding of the industry without
understanding that component.

------
advertising
Good book on this and other collecting aspects - Art Collecting Today

[https://g.co/kgs/UBo4YM](https://g.co/kgs/UBo4YM)

------
ApolloRising
I'm interested in the data visualization aspect of the DB. Is there somewhere
we can download the database to run queries against it in Tableau?

~~~
Artnome
I'd like to open source at least a portion of the data to see if it is
possible to build a community driven database. Could connect works back to
museums and auction records as well as articles and research and potentially
build a crowd sourced provenance.

