Fun with Infant Mortality

From: Nick Brooke <100270.337_at_compuserve.com>
Date: 21 Nov 94 15:07:09 EST



Paul Snow defends "real world" infant mortality rates in Glorantha.

I used to do this, too, until I studied the UN's model life tables. I'll reprint one as an appendix to this posting. Essentially, using genuine rates for infant mortality makes life depressing for players and referees alike. I agree with Sandy: as there is no fun and no benefit in using the historically accurate rates, stuff them.

Gloranthan populations are "suppressed" by the increased vim and vigour with which magically-backed disasters afflict them, and by the need to support the children you might otherwise produce like rabbits. Exposure of unwanted infants happened in ancient Greece (and probably elsewhere): population *doesn't* just go exponential in the absence of controls. If it did, after all, we'd all be broos. Glorantha ain't Malthusian.

Those proposals:

> Glorathans are habitually more continent than Terrans.

Unlikely, as this would be No Fun.

> Contraception, probably magical, is widely practiced.

Probably "is widely available" would be truer, IMHO. What do you mean by "probably magical"? Herbal recepies are magical, aren't they? Or do you want an Abortion rune spell, as lambasted by Greg in Tales #7...

> Nature, unlike some manisfestations of human justice, has no
> proscription against cruel and unusual punishments. Wouldn't
> another view be to say that by facing these forms of tragedy
> in the game we can better cope with them in life?

Here are the stats for the *degree* (not form) of tragedy real-world life models would impose on Glorantha:

______________		____________________________
Male survivors		Expectation of life at birth
to exact age		 20	 25	 30	 35
		
0			1000	1000	1000	1000
1			 668	 710	 744	 775
10			 445	 524	 589	 646
20			 392	 472	 541	 603
40			 242	 318	 392	 464
60			  79	 132	 194	 263
______________		___________________________

Source: "Methods of Population Projection by Sex and Age," UN Population Studies 25 (New York, 1956).

Pre-industrial societies before the modern demographic revolution tended to have an e0 (expectation of life at birth) of 20-40 years; an e0 of 30 is a reasonable assumption for the senatorial classes of the Roman Empire (source: Keith Hopkins, "Death and Renewal," Cambridge 1983).

Interpretation: if life expectancy at birth is 25 years, then for every 1000 children born, 290 will die before their first birthday; just about half will reach their tenth; less than half will survive to RQ's average player character age. There's a *very* steep initial fall, followed by a gradual decline. Sandy and I would cut out the steep start but presumably keep the rest of the population age-distribution intact. If you like to draw graphs, you can make a good stab at one from this info.

(One less moralising objection to infant mortality is that, if a referee has to think up twice as many childrens' names for every clan or family, he will swiftly become pissed off... and an irritated referee is nobody's friend. Pendragon-esque family campaigns are far easier to enjoy if an "unrealistic" number of kids survive to initiation age).



Nick

Powered by hypermail