Trade Research from Quietus' Quick Economics Guide

[therother]

This thread has been created from Quietus' A Quick Economics Guide & Primer to RTW, which now resides in the RTW Guide forum. Below are posts in that thread that related to trade research.


Original post:

Looks good Quietus

A couple of very, very quick notes, after skimming the article at ridiculous speed.

but since there are no base trade values attached to each commodity/resources it is very difficult.

You can find these in descr_sm_resources.txt.

The population of a city affects trade income.

There are a few other things that you say that I think may be inaccurate, but I'm not sure of my facts. If I find the time I'll check and report back.

[therother]

A few slightly more detailed comments:

You might want to mention expenditures like Family member wages (200 each I think, 300 for the Faction Leader), devastation, diplomatic tributes in your opening list. You might also want to mention one time incomes/expenditures, like Senate fines or selling map information.

I have two test provinces with the same population and the same taxes, but the equation for this relationship is nary obvious.

You have two settlements with the same population, no Governors, same tax rate, same difficulty level, but have different tax incomes? I've never seen this in my games. Would you mind making the game available to me? I thought I had tax income pretty much solved. Ho hum.

Trade

In my games the increase due to paved roads is 100%. It's 50% for Highways. For increases in neighbouring settlements, it usually depends on the relative quality of their roads, from my limited experience.

Sea Exports/Imports - It's been my general observation, as yet unconfirmed, that your trading routes depend on a number of factors. Geography is one: you only seem to sea trade within a certain locality. Selection of routes is based on profitability of the route. The game automatically chooses the best route for trading. It takes into account trade agreements, and is strongly dependent on both the goods that you can trade to a settlement (i.e. if a target settlement has that resource as well, it will not be traded), and the populations of the two settlements.

Basically, the more populated the market is, the more money everyone gets (imports and exports). A very large city, which is centrally located around a number of large cities with lots of trade goods, will not only make a great deal from exporting, but also a fair amount from importing. This is why, along with tax income, you want your cities as large as you can make them.

How he managed to calculate the distances by tiles, I do not know.

In the first instance, the fool counted squares from known landmarks (Wonders, for the most part). He then learned of the show_cursorstat RomeShell command. Unlike other RomeShell commands, you can use this as many times as you like. It's then just a question simple of trigonometry.

Trade Fluctuations - I suspect this is to do with population changes.

[Quietus]

In my games the increase due to paved roads is 100%. It's 50% for Highways.

Oops, typo. I quickly checked my conclusion papers, I did put down "road -->paved = 2x" too. I'll double-check the mess of data papers to be absolutely sure.

Trade Fluctuations - I suspect this is to do with population changes.

The increments do not happen concurrently though. Example, land trade w/ settlement A,B,D, increases but not C,E etc. Or you're saying population changes in the others settlements not the original?

Basically, the more populated the market is, the more money everyone gets (imports and exports)

I have to dispute this. I checked for population effect on trade but there's no relationship I've seen. For example: Tingi gets 1700+ denari income from exporting the same stuff to Corduba, but only about 200+ denari with Carthago Nova. Maybe it is distance related?

Originally Posted by Quietus
I have two test provinces with the same population and the same taxes, but the equation for this relationship is nary obvious.

You have two settlements with the same population, no Governors, same tax rate, same difficulty level, but have different tax incomes? I've never seen this in my games. Would you mind making the game available to me? I thought I had tax income pretty much solved. Ho hum

No governors, Normal tax, no Rebels, same difficulty level, in-game (Arretium and Arimium). SAME taxes collected, same population.
Arretium = 5232 pop, 745 denari tax.
Arimium = 5230 pop, 745 denari tax.

Uhm, sorry, I'll check your old posts.

Sea Imports – Sea import income is ALWAYS 20% of the exporter income.
Example:
Settlement A has a 100 denari export income for exporting to Settlement B;
Settlement B gets 20 denari Sea Import income as a result.
This is regardless of roads, trade buildings, ports, governors or any other factors that are involved in the trade. There can be possible limits to this relationship (see Sea Import Routes).
Sea Import Routes – You can see them by which directions the trade ships are moving. There are instances that Sea Import income isn’t being reported, despite a Sea Export to that settlement is being reported in another town. Thus, there may be some cap that limits how much can be imported by a town. Unlike, sea exports where the number of routes are determined by port type, this is not so in sea imports. More tests will be needed.

2. 2 cities can export the same resource to a city. While both of those 2 cities get export income, the city being exported to gets import income from only one of them.

Andrew, is that what you're replying to? Oh nice, will have check this out.

I'll attend to all your comments, infos, and corrections. Thx for the replies, and again please, if you find any mistakes, speak up.

[therother]

The increments do not happen concurrently though. Example, land trade w/ settlement A,B,D, increases but not C,E etc. Or you're saying population changes in the others settlements not the original?

I'm not sure, I'd have to see your data to see exactly what you mean.

I have to dispute this. I checked for population effect on trade but there's no relationship I've seen. For example: Tingi gets 1700+ denari income from exporting the same stuff to Corduba, but only about 200+ denari with Carthago Nova. Maybe it is distance related?

I think perhaps distance is a factor, but trade income is most definitely affected by population. Absolutely no question - I've seen what happens when you change populations. You lose money from exports, the imports you already get, and you might lose entire import routes. [see example]

Tax: Sorry I misread the original post. Damn my speed reading skills. OTOH, I'm not meant to be 'wasting' time here at all...

Of course, I forgot another geographical restriction on sea trade: you can't sea trade with a settlement you have a land route with! But maybe that was obvious.

Oh, and trade income doesn't seem to be affected by campaign difficulty.


Hacking Athens down by 75%

 
Pop	30074	7500		Pop	Goods
Land
Lari	547	518		28414	Ag,Fe, OO
Therm	549	520		29777	Ag,Fe, OO
Cor	595	555		17949	Ag,Fe, OO,Tim,Marb
Imports
Spart	307	283		20830	Not Reported
Rhod	160	n/a		22515	Tim
Thess	145	134		23466	AU, Tim
Kyd	191	176		20564	Dye
Sard	166	151		16379	Tim, Marb,Text
Byz	120	n/a		23121	AU, Tim
Perg	161	147		18393	Tim,Wine,Text
Exports
Kyd	1364	1260		20564	Ag,OO
Perg	960	862		18393	Fe,OO
Sard	906	797		16379	Fe,OO

Totals	6171	5403

One thing to note: the trade income, as given in the trade summary scroll, is different than the figure given in the Settlement Details scroll. Is this just in my games, or is everyone seeing this? FYI, the corresponding drop in actual income is 7067 to 6165 Denarii.

[andrewt]

Andrew, is that what you're replying to? Oh nice, will have check this out.

I'll attend to all your comments, infos, and corrections. Thx for the replies, and again please, if you find any mistakes, speak up.

Yeah, that was what I was replying to.

For trade, distance seems to be the biggest factor. Halicarnassus and Rhodes are exporting 2000+ each to each other in my game. The largest sea exports tend to be cities right next to each other.

[therother]

If distance is a primarily determinate of the value of a route, then that would certainly explain the lack of really long trade routes in the game. I have some fiendishly simple ideas to test if this is indeed the case, but they will have to wait.

Just noticed an odd thing: the trade income from Byzantium (to Athens) dipped (~7%) when I constructed the Imperial Palace. It only went back up to its previous level when I built a Curia. Very curious indeed.

No time to investigate further on either point though. Perhaps tomorrow.

[Tamur]

the trade income from Byzantium (to Athens) dipped (~7%) when I constructed the Imperial Palace.

I've had the same thing happen when finishing trade-building upgrades. I finally did find my data file from that test I ran two weeks ago. Will have to dig it out and get some income-dip percentages for each of the buildings, but it was quite consistent IIRC.

[Tamur]

Also re: trade distance, there must be something to this. The largest income cities I've ever had have been pairs like Londinium/Samarobriva, Corduba/Tingi, and Patavium/Ariminum.

Didn't think about that at all until I saw your post andrewt, good point.

[therother]

Also re: trade distance, there must be something to this.

A bit more data, this time from Kydonia:

Pop	Import	Town	DisCity	DisPort
16379	469	Sardis	25	15.5
18595	489	Perga	30	20

DisCity is the city-city straightline distance.
DisPort is the straightline distance from the rally point of each port.

Only thing I would say is that it may go on the length of trade route itself, which is much, much harder to quantify.

[Quietus]

I'm not sure, I'd have to see your data to see exactly what you mean.

Example: N.M (forgot which test was this)
Prov. (turn)(turn+1)(turn+2)
Land trade:
Lem (149)(150)(152)
Lug (204)(205)(205)
Mas (118)(119)(120)
Osc (78)(79)(79)
Sea Imports:
Arr (93)(93)(99)
Seg(80)(81)(81)
Sea Exports:
Arr (319)(320)(321)
Pal (273)(277)(278)

What's causing those tiny number increases? When testing and calculating 40 denari values and lower, you can understand how it can change the deviation by a lot.

Quote:
Originally Posted by Quietus
I have to dispute this. I checked for population effect on trade but there's no relationship I've seen. For example: Tingi gets 1700+ denari income from exporting the same stuff to Corduba, but only about 200+ denari with Carthago Nova. Maybe it is distance related?

I think perhaps distance is a factor, but trade income is most definitely affected by population. Absolutely no question - I've seen what happens when you change populations. You lose money from exports, the imports you already get, and you might lose entire import routes. [see example]

Interesting results. I also forgot to mention that Carthago Nova has about 16000+ pop while Corduba has 15000+ pop. Perhaps, distance is a much bigger factor. Also, no trade buildings were destroyed when you reduced the population?

Quote:
Originally Posted by therother
the trade income from Byzantium (to Athens) dipped (~7%) when I constructed the Imperial Palace.

I've had the same thing happen when finishing trade-building upgrades. I finally did find my data file from that test I ran two weeks ago. Will have to dig it out and get some income-dip percentages for each of the buildings, but it was quite consistent IIRC.

That is weird. So there's level-dependency too when factoring trade income? BTW, the trade routes never changed at all?

[therother]

A bit more data, this time from Tarentum.

Pop	Exports	Town	DisCity	DisPort	Resources	
15516	1436	Salona	12.5	9	Only Cu
28733	1296	Apollo	10	4.5	Cu, Timb
29777	613	Therm	20	11.5	Cu, Timb

Only thing I would say this time is that Tarentum is my capital, and I've always suspected funny things happen with it.

Oh, and if you notice that Apollonia is ~half the distance than Thermon, and the income is also roughly half, despite having similar populations. So, my current theory is that distance plays a major role, whilst population plays a more minor role.

[therother]

Also, no trade buildings were destroyed when you reduced the population?

Absolutely nothing changed but the population, not even the date!

So there's level-dependency too when factoring trade income? BTW, the trade routes never changed at all?

No changes, no. I'm being to suspect a situation similar to what it was for squalor - only more complicated! Which if it is, I think we may never get a good handle on the numbers, unless a Dev comes in and gives us the equations behind them.

Edit: Thanks for the numbers. Some of them could well be population changes, but one or two look a bit odd.

[therother]

Final bit of data for now:

This is taken from Croton before and after I declare war on the other Roman factions (which own Messana and Syracuse)

Pop	Exports	Town	DisCity	DisPort	Goods	
15516	880	Salona	18.5	17.7	Ag	
14098	805	Mess	10	9	Ag	Ally,Trade Agreement
21950	764	Syra	15	17.2	Ag	Ally,Trade Agreement

Pop	Exports	Town	DisCity	DisPort	Goods	
15516	880	Salona	18.5	18	Ag	
28733	590	Apoll	11.5	14	Ag	
29777	491	Therm	18	15	Ag

[khelvan]

Do you mind if I post some of your work to the Rome Wiki we have set up?

Or would you like to contribute yourself, perhaps?

http://www.kanwei.com/romewiki/

[Tamur]

therother is busy working on RL, I'm fairly certain he won't have the time to add this to the wiki. Unfortunately same for me here for about a week at least, it's that time of the semester I guess.

One thing to add to the discussion: I did dig out my data from the 20-turn run I did with the Julii a while back. Here's some data of interest:

Arretium started with port, land clearance, roads.

• turn 1: tax income was 786, trade income was 210
• turn 12: tax income had grown 845, trade was 482. This was not linear with the population -- tax % dropped 3 points based on population + trade + farm incomes
• turn 13: finished market. tax income dropped to 774, trade income up a bit to 521.
• farm income throughout stayed basically the same

Ariminum started with land clearance, roads.

• turn 2: tax income was 697, trade income was 109
• turn 3: finished port. tax income dropped to 630, trade income up to 141
• turn 6: tax income was 648, trade income was 160
• turn 7: finished trader. tax income dropped to 580, trade income went up to 174.

So on average when completing trade upgrades, I got a 68 denarii drop in tax income, and a 28.3 denarii rise in trade income.

I had other completions but they were affected by environmental factors (governor changes, seiges).

I say to myself,

[Quietus]

No changes, no. I'm being to suspect a situation similar to what it was for squalor - only more complicated! Which if it is, I think we may never get a good handle on the numbers, unless a Dev comes in and gives us the equations behind them.

With the base trade value, it is definitely worth a couple of tests!! The numbers will be very helpful because I can now track how each values are increased!!

Do you mind if I post some of your work to the Rome Wiki we have set up?

Or would you like to contribute yourself, perhaps?

Are there dedicated editors or moderators in there that checks the data that comes in? I'm fairly concerned about the integrity of the data and information that's gonna be posted and edited. At least here, I can ask for feedback and responses that I can rebutt myself.