Tuesday, February 26, 2013

Downing the Disease Difficulty

So, let's do some simple design, just to get a handle on some new rules for disease.  Disease is one of those things in the game that everyone hates, players and DMs alike, because it is so random, so out of the blue and in turn so deadly, it seems grossly unfair to arrest a player in his or her tracks just because the percentile dice comes up '01.'

Looking at the vegetation map I posted for Dalmatian Lands yesterday (the second map down the page, mostly green and yellow), the gentle reader can see numbers that are black on white.  These are degrees of civilization, or what I was calling 'infrastructure' nine days ago.

(See?  There is method to my madness.  First, I introduce the math, then the data, and finally the purpose)

Let's take a wide variety of places.  We can pluck them all from southern Italy.  Hopefully, the reader can find Naples ... its in the middle of a bright yellow area in the lower left quadrant of the map.

Naples has an infrastructure (IS) of '3478' ... which is the highest number I could find anywhere that I've actually calculated.  Paris might be higher, but I haven't actually calculated it.  The number is based on the relative density, and in the middle ages, the density around Naples was HIGH.  It was, at that time, one of the most urban places on earth.

Above and to the right is a hex with Benevento, with an IS of '456.'  Two hexes to the upper right, the reader can see Lucera, with an IS of '88.'  One hex down and to the right of Lucera is an empty, dark green hex with an IS of '30.'  And up and to the right of Lucera is a empty, light green hex with an IS of '5.'

Let me blow up the relevant area so it's convenient.  The places I've described are makred with blue arrows.

Now, it can be seen that there is another small number in the right corner of every hex, in black.  In Naples, that number is 0.  In Benevento, it is 275.  In Lucera, it is 610.  Finally, in the dark green hex it is 2814 and in the light yellow hex (near San Severo) is 2109.  These are elevations, in feet.  On the original map, the reader can see that these elevations (and the low IS numbers accompanying them) follow the Apennine Mountains down the spine of Italy.

Let's take advantage of these numbers being based on density and lets say that the number itself, divided by 10,000, gives the % chance for becoming diseased if you spend a night in that hex.

WHOA!  A 35% chance for disease if you sleep in Naples?  Ridiculous! The population would all be dead!

Yes, that is probably correct, except for a few points I'd like to make.

First, I said becoming diseased, not catching a disease.  I'm arguing that you will contract something that first night ... but not that there is then again a 35% chance of catching something completely different the next night.  What I'm saying is that if you lie down in a gutter for three nights in Naples, then yes, by the end of the third night, you will probably be sick with something.

Second, I must rush to point out that in all probability, most persons in the medieval world probably were diseased ... with things we hardly think about: a wide variety of skin maladies, fungus, moderate pneumonia or tuberculosis, not to mention tape worms and other internal beasties, scabies, mild forms of disentary, scurvy and a host of vitamin deficiencies, etc.  All that and chronic malaria, for another thing, which was rife in 16th century southern Italy, particularly among the coastal urban population.

Finally, this is D&D ... so the reader should expect modifiers.  34.78% is just a base figure.

Note, however, that as one gets further and further from the city, climbing up into the mountains, the character actually becomes safer.  Don't want to die of disease?  Don't go to town.

Paladins, naturally, are immune from disease anyway, and they could keep the diseases of a small party fairly at bay.  But a lot of time spent in Naples could make cure disease as useful as cure light wounds.

Features that would prove useful combatants against disease would include public baths, the prevalence of falconers and rat catchers, wells for fresh water (if it was fresh - wells helped kill people of cholera in 19th century London), hospitals, apothecaries and gong pits (which would presume a steady effort to clean up).  Dug sewers, too, would be a feature which I hadn't mentioned before.

This is Naples, however, with a population exceeding half a million and surrounded by a million more in the surrounding cities and duchies.  So it can't be a question of whether or not Naples has sewers, gong farmers, a hospital and so on.  Obviously, it would have many hospitals, and lots of everything else besides.

What matters isn't the presence of these things, but the degree of presence.  And here we get to pull away from the flat numbers.  Has the town kept up the sewers?  Are the hospitals intelligently run, or are they warehouses for the dying?  Are there enough apothecaries, gong farmers and rat catchers?  Is the water in the wells very fresh or awfully tainted?  What standards apply to the baths, and are they in the best of maintenance?

Suppose we make a supposition that each feature (seven in total, baths, ratters, wells, hospitals, apothecaries, farmers and sewers) has the potential for reducing disease in that area by 18%.  Thus, the potential could be to eliminate disease in Naples.  More to the point, however, 3d6 are rolled for each feature to see what is effective, and how much.  The average says disease will be lowered, in toto, 73.5% ... but a couple of bad rolls could make Naples into a disastrous vacation choice.

The same rolls are applied to every hex ... that is, that has a town (please note that the danger of disease applies to staying anywhere in the given hex, not just the town itself - though you could double the number for the city and halve it for the country, if you like).  Benevento and Lucera are a lot smaller, so they have less of everything ... but they also have less disease to combat (Benevento a base of under 5% and Lucera with a base of under 1%).  All in all, both could be quite decently safe.

The hills, of course, could not have sewers or baths ... but 'hospital' is a fairly wide term and in any case, there could be a local physician, along with a local herbalist and rat catcher.  Overall, there would be slightly less reduction ... but there's also a lot less disease to reduce.

Now, once the party is informed of the principle, they would know what chances they were taking ... by actually assessing the local towns.  They'd be asking after hospitals.  They'd be tasting the water upon arrival.  "Is there any evidence of sewers?"  "Have I even seen a rat catcher today, or someone with a falcon?"  And so on.  Bang.  A town now is more than just a collection of houses.  The players care what the infrastructure is.

More to the point, it would be REALLY HARD to raise Naples' sewer system from your ... call it a 'mitigation' roll ... of 7% reduction to an 8% reduction.  That's a lot of time, labor and money, where it comes to rebuilding parts of disease-infested Naples.  But improving Lucera by 5% might be something a mid-level party could manage - now that there is some logic to what needs to be done and how it is to be done.  The town has one crappy hospital - build another.  The town's baths are basically three natural ponds.  Let's shore them up and make the townspeople appreciate us.  "Let's spend our money on something concrete, as opposed to just more armor!"  And let's have some adventures grow out of the struggle to overcome the miserable process of living ... when there are people out there to oppose or help our efforts.

You want an adventure?  There's an adventure.


jbeltman said...

I guess you are firmly in the 'low fantasy' camp.

Of course this kind of stuff just makes the imagination go crazy.

It makes where the players live a much more important choice, perhaps a villa in the countryside near a large town if they are rich enough. Different areas of town would have different chances of disease making them want to move out of the slums a lot more.

Clerics have much more to do now in town.

The 3d6 roll can be used as the appropriate score for the person in charge of the particular area. So an 18 in hospitals means the person in charge of the hospitals is a regular Florence Nightingale. A 5 in baths means that they are the province of the baron's no good brother.

It also makes me think of the story of Dick Whittington (http://en.wikipedia.org/wiki/Dick_Whittington_and_His_Cat). The presence of cats or other animals could make an area more or less disease ridden. I also like the idea of some type of creature moving into the sewers and eating all the rats so that the chance of disease goes down substantially in a short period of time. The players would like it initially but how quickly would the penny drop? Would they catch on in time and go exploring to see what is happening before the creatures come pouring out of the sewers in plague numbers?

Lukas said...

As the complexity of the populated environments increases, and hopefully the interest, do the classes keep up with these changes?

Or do you think some growth could be given to the classes to make some as capable in the city as the druid or ranger is in the wilderness?

Ozzie Pippenger said...

Nice post.

Have you considered tracking each disease or type of disease separately? For example, stagnant water could increase cholera chances, a lack of rat catchers could increase the chance of Black Plague, and an abundance of brothels could increase the chance of Syphilis. It could get confusing to calculate the chance of ten diseases for each hex, but I don't think one flat number for all disease quite cuts it.

One other thing. Do you have any kind of plan in place for the large scale spread of disease? If the party is in a French village and they hear about an outbreak in London, what chance is there of the disease reaching them and how fast will it do so?

Alexis Smolensk said...

All those ideas have merit. I had thought of specifying which disease by which particular method of health, but I did not need this post to run into another thousand words. Besides, at some point you have to do work.

Remember, Lukas, I do have well rounded secondary skills for characters. Consider how helpful Lukas the character's knowledge of architecture could be.

Lukas said...

Perhaps if you thought about it differently determining the disease is easy.

The new star wars game as a system that is similar, but could be applied differently...

Roll to determine if a disease if any is obtained.

Roll again on a % disease chart that is based on the possible types of diseases based on the infrastructure services.

Heck, if you're really slick maybe the fail region would be divided by disease so only one roll is needed.

Given Alexis uses excel this is not an unlikely possibility for the single roll.

Alexis Smolensk said...

To be honest, I didn't agree with Ozzie that one roll didn't cut it. Obviously one roll has 'cut it' for forty years in D&D. So I had not considered changing from one roll vs. disease, and using the random table from the DM's Guide.

But your solution is elegant, Lukas. I very much like it ... even if it means ultimately subdividing the diseases into seven categories.

Anyone out there want to give that a try? Like I said, the DMG has all the diseases divided by parts of the body affected.

Butch said...

Considering John Snow didn't make the connection between contaminated water and cholera until 1854 -- and wasn't widely accepted until almost the end of the 19th century -- would you allow players to apply that knowledge to improving Lucera's health in 1651?

Alexis Smolensk said...

Yeah. I was reading about Snow just last month in Bryson's book. Snow died before his findings were confirmed. Damnable incompetence.

The spell purify water suggests that D&D druids, if not Christian Victorians, are more on the ball ... as well as 9th century Moslems, who were firm believers in clean water, having had much more experience with 'drink wrong water, die.' Remember too that the Italians, with their long history fighting malaria, were well aware that if you filled in the swamps, the malaria went away - so even if the specific disease of cholera was not understood, there are plenty of arguments for why the party might make efforts to improve the sewers, maintain the wells and clean the baths.

Butch said...

But that brings up another point. If you're the Catholic Church, would you support efforts to cure diseases through secular efforts like infrastructure improvements?

Or is it better that the poor huddled masses must go to the local Cleric and pray (and tithe) for a Cure Disease spell?

Arduin said...

Heyo! Trawling through the old posts again, and this one caught my eye.

Do you still use the disease %'s? I know you've added Health to your NTME modifiers, so what does it, in this case, modify?

I am endlessly pleased at how fruitful going through the archives is on your blog. I've never failed to find something fascinating that I had completely forgotten about.