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Old 06-09-2017, 04:35 PM   #1
hal
 
Join Date: Aug 2004
Location: Buffalo, New York
Default Converting prices in other game systems to GURPS

Hello Folks,
Rather than continue a divergence from other poster's thread, I decided to open this up, in case someone might find it useful. The original comment that sparked the response, and my reply to that response, was how to convert prices in one game system over to something that can be used with GURPS. In my next post, I will explain what I'm doing these days for conversions, and why. I see no reason why people can't offer up their own methodologies and why they do it. This may give ideas to readers on how to convert prices from different game source books. :)


Quote:
Originally Posted by Bruno View Post
What was the URL? It might be in the Internet Archive, and I'd like to see it.
Originally, when I attempted to go back to my old web page at waybackmachine, I couldn't get past the robots thingie that barred me from accessing my old web page. Today, when I used an old URL to the waybackmachine that directly linked to my old web page, I was shocked to find it worked!

So, without much further ado...



REVISIONS Where I examined the data from C&S 3rd edition, found flaws from the analysis, and offered suggestions for fixing it.

FARMING - using the revenue generation for farming by means of Chivalry & Sorcery's third edition rules, but modified for use with GURPS rules. The money values were fixed at $4 GURPS = 1 silver penny. A practice I now no longer advocate.

REVISED INCOMES This is where I attempted to fix the issues that someone missed when they published the Fourth Edition rules. I noted at the time, that the historical wage for Mercenary knights with a horse, was 2 shillings per day, which works out to 12 silver pennies to a shilling, or a total of 24 silver pennies. In the revised Incomes table I calculated - this is exactly what the mercenary knight would earn.

Much of this information probably won't make sense unless you can get your hands on Chivalry & Sorcery fourth edition (or the earlier Chivarly & Sorcery 3rd edition say, from Ebay). However, as fate would have it, RPGNOW.COM has the Chivalry & Sorcery REBIRTH edition (4th edition), available for free download HERE.

If you're going to navigate to various web pages on my now defunct web site, it is advised that you use the links at the top of the page rather than anywhere else. These seem to work relatively consistently.
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Old 06-09-2017, 05:21 PM   #2
hal
 
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Default Re: Converting prices in other game systems to GURPS

Converting costs from one game system to another is mostly an art rather than some rigid mathematical formula that can be used without fail. The idea is, to compare whether a fictional character in a game, can purchase the same items in one system versus that used in GURPS.

So, let's take an example in which the use of a strict mathematical formula is not always a good idea.

Let's say, that you want to use the concept, that $4 GURPS is equal to 1 silver penny in an era similar to say, England, circa 1200 AD.

So, lets say that you have a +2 sword versus males, plus 1 versus anyone? We'd enchant that sword so that it was +1 damage (250 energy). Then we'd enchant "Bane: Versus males only" for 100 energy. And finally, we'd enchant the +2 aspect of the Puissance spell, that normally costs 750 energy (1000 energy less the original 250 energy to get the +1 damage). Since this is a function of the bane enchantment, the 750 energy is halved to 375 energy. Total resulting energy spent to enchant such a sword, would be 250 + 100 + 375 or 725. At $33 per energy for slow and sure enchantment, such a blade would be worth 33 x 725 or $23,925.

Now, converting that to a game system where a day's wages is 2 silver pennies per day, or about 44 silver pennies per month - in which the job might be deemed to be "Struggling" in GURPS, would mean that a month's wages is about 88 silver pennies per month.

Now, in GURPS, a normal month's income is about $700 for TL 3. Dividing the Total cost by the average income for a month, gives us 23,925/700 or roughly 34.18 month's worth of cost/income. So, in a game system in which the person makes 88 silver pennies per month, the cost of the enchanted blade should be 34.18 x 88 or 3,007 pennies.

What would that price look like had we used a conversion rate of $4 GURPS = 1 silver penny? 5,981.25 silver pennies. Clearly a significantly higher cost value than the prorated value calculated earlier.

So, let's take a hard look at why this is necessary. If you look at the web page HERE that lists historical prices gleaned from various books (Usually Gies and Gies books), you will note that an item listed as being

Laborer 2/year max c1300

A pound sterling back then, was 20 shilling to a pound, 12 pence to a shilling, or 20 x 12 silver pennies. That's 240 silver pennies for our labor's yearly income x 2 (maximum income circa 1300 AD). So, 480 silver pennies max income for a laborer works out to roughly 40 silver pennies per month. Since GURPS defines this as being roughly "Struggling" income, a normal person's income should be about 80 pence.

What was the cost of a horse in about that same time period?

Knight's 2 horses 10 1374 " 76


So, one such horse would be around 5, or roughly 5 x 240 or 1200 silver pennies. Our laborer earning 40 silver pennies per month would have to work roughly 30 month's worth of time to earn an amount equal to five pounds sterling.

That's a NORMAL riding horse, not a war horse, so, how would that translate in GURPS? If a struggling job earns about 1/2 the income of normal income ($700), then $350 is the income for our laborer (in GURPS equivalence) and 30 x $350 is about $10,500.

Otherwise? $4 GURPS = 1 silver penny formula, would result in the horse being worth a mere 1200 x 4 or $4,800.

Two widely different values arrived at by two different methodologies.

Why do I peg it at a month's income rating rather than a straight formula? A struggling laborer in the one system, can purchase about the same items in EITHER "system" (whether a game system, or a historical evaluation of goods etc).

Where does this break down? It breaks down, if when using say, Dungeons and Dragons, the price for an object is not reasonably priced to begin with. But the general result is about equivalent when you put it terms of "buying power" rather than in terms of specific currency conversion formulas.
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Old 06-09-2017, 06:37 PM   #3
Nemoricus
 
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Default Re: Converting prices in other game systems to GURPS

If I understand this correctly, what this essentially does is give you a conversion factor between the real world currency and GURPS dollars.

So, for the 1200 AD silver penny, the conversion factor works out to G$8.75 per 1200 AD English silver penny.

Since 5 pounds is 1200 silver pennies, 8.75 times 1200 gives us G$10,500 for the warhorse, or the same figure you came up with.

Basing the conversion factor off of the monthly income is a great idea, though, since it gives a common frame of reference. However, once you have that factor, it's a lot simpler to convert prices.

Now my question is: Given reasonable prices that are correlated with typical wages of the day, what would make this method fail?
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Old 06-09-2017, 07:09 PM   #4
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Default Re: Converting prices in other game systems to GURPS

Quote:
Originally Posted by Nemoricus View Post
Now my question is: Given reasonable prices that are correlated with typical wages of the day, what would make this method fail?
Historical prices, especially for individual items rather than bulk commodities, is often mostly guesswork, almost all games price based on in-game utility to at least some extent, and utility is dependent on on what the game models and how. Therefore conversions may result in items that players feel are over or under priced compared to alternatives.
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Old 06-09-2017, 08:49 PM   #5
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Default Re: Converting prices in other game systems to GURPS

Monthly income is also a variable target, which can make it difficult to do the first part of the equation.

Whose income? Doing what job? Where? Which month? Which year?
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Old 06-09-2017, 09:03 PM   #6
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Default Re: Converting prices in other game systems to GURPS

Quote:
Originally Posted by Nemoricus View Post
If I understand this correctly, what this essentially does is give you a conversion factor between the real world currency and GURPS dollars.

So, for the 1200 AD silver penny, the conversion factor works out to G$8.75 per 1200 AD English silver penny.

Since 5 pounds is 1200 silver pennies, 8.75 times 1200 gives us G$10,500 for the warhorse, or the same figure you came up with.

Basing the conversion factor off of the monthly income is a great idea, though, since it gives a common frame of reference. However, once you have that factor, it's a lot simpler to convert prices.

Now my question is: Given reasonable prices that are correlated with typical wages of the day, what would make this method fail?
The thing to keep in mind, this process does NOT care about historical prices or fantasy prices from another game system that uses a totally made up system of currency and/or pricing.

Put another way? If a character is created in a game system called "D&D" and D&D has a common average income for zero level characters, or perhaps the "gold standard" for normal monthly income is a fifth level character.... it doesn't matter. As the GM trying to convert things, you have to know what the economics aspect of the game system is in order to determine the standard of "monthly income units". In theory, if CP2020 references the concept that most average monthly income is 1,000 Eurodollars, and something costs 4,500 Eurodollars, then in GURPS, you have to determine what the average income is at the same TL for CP2020 (which would be, for 4e, TL 9 I believe) and then reference the general cost of a cybernetic item as being 4.5 months income, and convert that to 4.5 x GURPS monthly income.

Same thing when converting from a GURPS price to a C&S price. If a normal person could expect to have to work 9.43 months to earn a given item in GURPS prices, then you would multiply the C&S monthly income by 9.43 to get its C&S price.

Keep in mind? The "formula" works for that ONE item ONLY. So something that costs 8 month's income in say GURPS, won't hold true for something else that in GURPS only requires 3 month's income. That is why you can't use a single "$4 GURPS = 1 silver penny" concept. Why? Because the price in GURPS system might not have the same ratio value of how many months it costs to earn that item, as a pre-existing SAME object in C&S.

A ratio system will work regardless of what item you're trying to determine the conversion cost should be. Saying that you should be able to take 100 items in GURPS, find their general conversion rate (the average of all 100 items) won't give you the proper approach.

So for instance? In one case, a horse might be 93 month's income. A sword might be 1/4 month's income, a fine sword might be 5 month's income, etc.

So it may come to pass, that while GURPS charges $600 for a broad sword, where a month's income is $700 per month, C&S might say that the same sword (Broadsword or arming sword) might cost 6 month's income.

So whose value for the sword is correct? GURPS? C&S? Historical weight (where some author dug into parchment records, translated it from abbreviated Latin in a world in which there is no standardized spelling - and hopefully got a reasonably accurate price)?

What I particularly liked about the LOW TECH rules for estimating costs for a given item (and conversely, how long it takes to make a given item if you reverse engineer it) is that Cost of Materials plus cost of Labor plus a slight markup equals market price for an item. Things that have an artificially increased cost (such as swords that are required to be sold at twice normal cost as a means of arms control) will encourage a black market environment In which items are sold outside of official notice.
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Old 06-09-2017, 09:15 PM   #7
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Default Re: Converting prices in other game systems to GURPS

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Originally Posted by sir_pudding View Post
Historical prices, especially for individual items rather than bulk commodities, is often mostly guesswork, almost all games price based on in-game utility to at least some extent, and utility is dependent on on what the game models and how. Therefore conversions may result in items that players feel are over or under priced compared to alternatives.
As I like to fondly use as an example too - what if, tomorrow, all records of horse prices were to disappear with the end of our civilization as we know it (say, a bunch of EMP's that destroy computer records and any device that can read digital information). Then further suppose, fifteen hundred years from now, some archeologist unearths a record of a Sheik purchasing a race horse stallion for 6 Million dollars. If that was the ONLY surviving record of horse values, what would our future archeologist think of the price for horses - especially if his document is fragmentary? Same here for medieval prices. They list the local transaction at the time, without noting what it cost overall in other locations, where the item, having been haggled upon differently, might be worth 20 sheep, and one goat, whereas elsewhere, it is recorded that a sword was traded for 10 silver pennies. Was it used and bent? Was it brand new from a neophyte weapon-smith? Was it the price of an established weapon smith?

When a game designer has NO foundation upon which to base their game design upon, their numbers will be whimsical and pulled out of thin air (for some giggles? Read the rules on ATLANTIS: THE SECOND AGE OMNI SYSTEM in which bronze weapons weigh 2/3rds the weight of iron weapons, and a bronze two handed sword weighs 20 lbs. A long sword weighs 10 lbs. Clearly, those numbers are pulled out of thin air <shrug>.

So, Sir_Pudding's comment is right on the money.
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Old 06-09-2017, 09:27 PM   #8
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Default Re: Converting prices in other game systems to GURPS

I think you misunderstood my intent. The conversion factor I derived is good for conversion for exactly one pair of eras/systems. $8.75 is the conversion factor for 1200 AD England prices to GURPS dollars, based on the numbers you provided. It does not apply to 1300 AD England, 1200 AD France, or D&D.

However, if you're doing multiple conversions with that pair, it's easier to calculate the conversion factor instead of going through the roundabout method of comparing monthly income every time.

What I did not say is that every silver penny is worth 8.75 GURPS dollars. I was very careful to always refer to the 1200 AD England silver penny, since that's the only time and place the conversion factor is good for.
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Old 06-09-2017, 09:42 PM   #9
hal
 
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Default Re: Converting prices in other game systems to GURPS

Quote:
Originally Posted by Bruno View Post
Monthly income is also a variable target, which can make it difficult to do the first part of the equation.

Whose income? Doing what job? Where? Which month? Which year?
And therein lies another issue. If you can find a similar job description between GURPS and say, Chivalry and Sorcery - then you try and use that one standard.

But then again, GURPS uses a somewhat arbitrary system for determining struggling incomes, normal incomes, comfortable incomes, and so on. If a game system charges say, 1 gold per level per day for the services of a mercenary - would that be another way of saying that at low levels, the job is struggling, but at higher levels, it is a Rich income?

This is why I say it is more of an art than it is a straight up mathematical formula where X = some function of Y. About the only method I feel comfortable after all these years (hence, why I use it) is to try and preserve the concept of buying power that economist use when comparing the buying power of say, someone from the 1400's AD in England, and someone in the present.

Which brings me to my next point...

For years, I've mentioned or commented in various threads, that I no longer use GURPS rules for income. The 4e rules are as written, acceptable for others to use, but I find that I only use it as a broad guidance aspect when dealing with economics and GURPS and other game systems. For Medieval game runs, I use HARN WORLD's system for goods and wages as well as services. I don't mix and match much unless GURPS presents something that clearly needs to be converted (such as magic items or potions). It was because of the alchemical potion costs that I started to look at the picture and say "Who can possibly afford to buy the potions of an alchemist?" It won't be those with struggling income, nor will it be those whose income is standard status zero for the most part. Why? If cost of living is $600 a month, and income is generally around $700 per month, a discretionary spending budget of $100 per month doesn't leave a lot of room for buying potions that cost in excess of $1,000!

Cost of ingredients plus time required to manufacture a given item, is the general price that is required to be paid or the manufacturer of the item will eventually go bankrupt/broke. Making matters more complex if you will, is the fact, that it is from the profits, that the Alchemist will make his monthly income, and from his monthly income, his cost of living deducted.

So, how many potions can an alchemist sell in order to make his monthly income? Who is he selling his product to? Those are questions that go through my mind. Why? If you have a city of 10,000 people, how many of those are going to be alchemists? How many can the city support before they start to starve because there isn't sufficient market traffic to keep them fat and happy?

Guilds usually FIXED prices at which things could be sold. Any guild member who sold things too low, could face fines (In medieval times). Likewise, if they sold it for too high a value, they could also be fined.

How much of this information is even in a GM's mind? Probably VERY little, or not at all. ;)

In the end, this "advice" is for those who want to find a method to convert prices from one game system to another for something that is either lacking in the other game system, but GURPS has, or is in another system, that GURPS lacks.

Using a peasant's income to buy a horse is bad. Using a Noble's income to buy a horse is probably closer to reality. But as you might guess...

The income for a Peasant doesn't seem to match that in GURPS as it might in another system. 2 pence per day for a thatcher (semi-skilled worker) versus 2 shillings per day for a knight with a warhorse. The income disparity is roughly what - 12 to 1? But so too are the cost of living issues. Stabling a horse is costly, and comes out of the Knight's money pouch. After you remove all of the mandatory expenses from his horse, the knight might see maybe 18 silver pennies income per day (or less!). So - therein lies the "Art" aspect versus the "simple math" process.

BUYING POWER. A concept that I stole from the economists discussing the economics of medieval times. Hence, the ratio system.

If anyone wants to point out their method, with examples of how it works, I'd say "post it here!". The purpose of the thread is to expose the reader to ideas. Me? I'm an old fart who largely runs his games his way. When I found out that my daughter cheated on her tests in High School, she made me feel MORTIFIED. See, when our group gamed together at my house, she was made to go upstairs, and adults talking about adult themes at the table - well, nuff said right? She bragged that because of gaming, she never bothered to open up the books to study or even read in class. She aced the test strictly on how I'd run my medieval fantasy campaigns.

My concern, is that she picked up an education, that while somewhat useful in some areas, exposed her to adult concepts a wee bit sooner than any father would desire to see in his kid. Then I stop worrying because I face palm myself saying "internet and modern society" She probably got a more intense education on those merits alone. :(

Well, I digress. For two people who approached me for my Harn FANTASY GROUNDS 2 campaign, they'll get a taste for my GM style. Hopefully, it will please them or keep them happy. Set in Harn, with Knights riding with their Liege Lord the Earl Caldeth of Vemion, the adventure hopefully will acquaint them with not only the sword and sorcery fantasy game world of Harn, but also give them a chance to interact with 50 plus families per manor they hold, and deal with other issues than simply swinging a sword at a monster. Who wants to be asked by a dance partner "care to dance" at a ball, only to have to examine their character sheet and groan because they don't have dancing as a skill and have a character who could be described as "having two left feet"?

Ah well, end of digression. ;) Have a good day folks.
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Old 06-09-2017, 09:45 PM   #10
hal
 
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Default Re: Converting prices in other game systems to GURPS

Quote:
Originally Posted by Nemoricus View Post
I think you misunderstood my intent. The conversion factor I derived is good for conversion for exactly one pair of eras/systems. $8.75 is the conversion factor for 1200 AD England prices to GURPS dollars, based on the numbers you provided. It does not apply to 1300 AD England, 1200 AD France, or D&D.

However, if you're doing multiple conversions with that pair, it's easier to calculate the conversion factor instead of going through the roundabout method of comparing monthly income every time.

What I did not say is that every silver penny is worth 8.75 GURPS dollars. I was very careful to always refer to the 1200 AD England silver penny, since that's the only time and place the conversion factor is good for.
The conversion process works for any currency you care to mention, both real and fictional. It is a process designed specifically to work so that you can find how to shoehorn in, items that exist in one game system, but not in another, or from realistic prices to a GURPS Analog, or even from say D&D to T&T (Tunnels and Trolls). So, don't sweat it either way. It is merely advice that can be used or not, as the reader here sees fit. Now, those who might want to simply things - might use the approach you suggest. If they do, good for them. I promise, I won't lose sleep, and I won't think less of them (hell, I won't even KNOW!) ;)
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