[MUD-Dev] DGN: MMOG Game Economies

William Leader leader at k2wrpg.org
Wed Nov 2 05:56:58 New Zealand Daylight Time 2005

Christopher D. Chapman wrote:

> I'm pretty much of the firm belief that a scaling system of 'pay for
> training' that links xp to gold will help create a single currency
> (instead of the two) and solve all of the issues around the rampant
> inflation in these games.  i've written up a moderately brief piece
> evolving from a bit of stream of consciousness rambling.

>   http://www.writely.com/View.aspx?docid=ac6vt6kwbxtj

As I read the essay I realized just how familiar this topic is to
me. Lets just make sure I understand the point you are trying to
make. Inflation in Game Economies is bad, and that you suggest it
could be fixed by blurring the lines between experience points and
money. You also suggest the traditional money sinks don't work
because they aren't exponential like most leveling systems are. I
will agree that they don't work forever because the amount of money
they consume eventually becomes trivial. I could go off on another
tangent here about why else they are bad, but then this list is
exceedingly good on following wild tangents.

About a year and a half ago when I had gone back to college and was
enrolled in a Macro Economics course I got very interested in how
what I was learning in class could be applied to games. To cut a
long story real short I'm going to point out the conclusion that I
came to after a semester of conversations with the professor, and an
equal amount of time modeling game economics.

Most of us in our lives eventually have to learn what to do with our
money. Do I buy good food and rent a nice place to live, or do I buy
Ramen Noodles and live in hovel so I can buy the latest hardware
that the newest game requires? Deciding where the money goes is
something we all do so when confronted with the problem of too much
money we deal with it by looking for more places to spend it. Here
is the revelation. As the creator behind your own little in game
economy, you don't just control where the money can go. You also
control where the money comes from. That is the most important part
to remember.

Now that this nugget of knowledge is out in the open what to do with
it? Well remember those models I talked about? The best answer I
found (not to say that there might not be better answers) is to
generate a price index on all transactions. In the computerized
environment you have access to something most economist can only
dream about. You know what price everyone pays for
everything. Through some math that is trivial for computers but I'm
to lazy to explain, you generate a price index. This is basically
the average price for any given item for any given player. When this
number is going up, you have inflation. When it goes down you have
deflation. Its a very easy indicator of what is happening in
game. Now the fun part is what do you do with it? Remember how I
said you control where the money comes from? It typically enters the
game in two ways. Cash reward after battles and quests (Why was a
snake carrying 2 copper pieces anyway?), and selling items gained in
battle or quests. The trick is to control how much money the player
gets at this point.

Lets assume that Cash rewards are static (they might be a random
range but that just makes the example hard). Lets also assume that
the target price index is 1 (because this makes the example easy.)
Now lets say that your typical cash reward is $10. but you notice
that the price index is up to 1.1 this is bad. so to curb the
inflation before giving a reward we multiply it by the target index
divided by the actual index. 10 x 1 / 1.1 = 9 (rounded to whole
number). So the index goes up players get less cash this counters
inflation. You can also use this for calculating the price merchants
pay for items too. Now if the index is down, then 10 * 1 / 0.9 = 11
(again rounded). Players have more money and this combats deflation.

What I find very compelling about this solution is that A) its
permanent. No need to add new sinks with new expansion packs so its
less long term work for the developer. B) its completely transparent
to the players allowing them to complain to the developers about how
some other class race combo has more buffs, rather than complain
about why rocks are so expensive.

So please please, developers... Try to think about the Spigot, and
the Drain when thinking about the Sink.

-William Leader
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MUD-Dev at kanga.nu

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