Individual’s Productivity:
Productivity at time t is a function of health, years of education, and age.

Education
Children can enroll in school at the age of 5. Primary school lasts for 6 years, and secondary school lasts for 6 years. In order to attend secondary school, the child cannot have opted out of going to primary school during any period. While primary school is free, secondary school is not, and costs the parents a constant amount throughout the game.

Individual and Family Effort:
Each individual’s effort is a function of his type (e.g. pregnant female v. baby). Total family effort is the sum of individual efforts. Total family effort is divided between production of maize, production of cotton, fishing, water collection, fuelwood collection, and small business. Children under 5 years do not contribute to family effort.

Agricultural Production:
Production of maize at time t is a function of individual productivity, effort (in man-hours dedicated to maize production), whether a drought occurs, presence of irrigation (which has a direct beneficial effect, and which also negates the effect of a drought), and then for each plot of land planted to maize, whether high yield seed varieties or fertilizer were used, soil health, and the base yield for maize.

Production of cotton at time t is a function of individual productivity, effort (in man-hours dedicated to cotton production), whether a drought occurs, presence of irrigation (which has a direct beneficial effect, and which also negates the effect of a drought), and then for each plot of land planted to cotton, whether high yield seed varieties or fertilizer were used, soil health, and the base yield for cotton.

Soil Health:
Soil only becomes depleted on a given plot if fertilizer has not been used for three years in a row, in which case output is multiplied by a depletion factor delta:

Drought:
D = 1 if PRECt is less than a given value (e.g. 1050 mm)

Water Collection:
Water collection is a function of effort-hours and the health of the people who put in that effort. When a water pump is installed, no effort is required for water.

Fishing:
Fishing Production at time t is a function of individual’s productivity, effort (in man-hours), whether the family has a boat, whether the family has a dragnet, and the stock size of the fishery at time t. However, if there is a family quota in place, the production will be the minimum of this function and the family quota.

Fishery stock size at time t is equal to stock size of previous year plus growth along a logistic curve, minus the harvest of previous year for the entire village (which is calculated by multiplying the family’s fishing by the number of households in the village, and adding some noise).

Fuelwood:
Fuelwood Collected at time t is a function of individual’s productivity, effort (in man-hours), and the stock size of the forest at time t. However, if there is a family quota in place, the production will be the minimum of this function and the family quota.

Forest stock size at time t is equal to the stock size of previous year plus growth along a logistic curve minus the harvest of previous year for the entire village (which is calculated by multiplying the family’s collection by the number of households in the village, and adding some noise).

Note: A family can collect more fuelwood than it needs for cooking, and sell the excess as charcoal in the town market.

Health:
Calories consumed by a person equal the sum of calories from maize and fish consumption, multiplied by an energy factor if there is insufficient energy for cooking. If school meals are in place, children will who are attending school will receive calories there also.

Energy factor equals the amount of energy available to the household from fuelwood and propane, divided by the cooking energy needs of the household. Note that a normal three-stone stove is less fuelwood-efficient than an improved cooking stove.

Note: Even if player owns propane, the “propane” variable equals zero if no propane stove is present.

Health at time t is a function of your health in the previous period, of your nutrition (the difference between your consumed calories and the minimal calorie requirement), and a boost if there is a clinic, a boost if there is electricity, and a loss if you are sick.

Sick at time t equals 1 if you have a water-borne disease, malaria, or a respiratory disease. Even if you don’t have any of these diseases, you get sick on 5% of turns due to random diseases (e.g. flu).

Water-Borne at time t equals 1 based on a probability. Your chances of having a water-born disease go up with a lack of enough water, and go down with good health, or if the village has a water pump and/or latrines.

Malaria at time t equals 1 based on probability. Your chances of having malaria go down with good health and if you have enough bednets in the home, and go up if the S-I-R model indicates that transmission potential is high.

Respiratory Disease at time t equals 1 based on probability. Your chances of having respiratory disease go up if you are a child under 5, and go down with good health, with an improved stove, and with a propane stove.

Death:
Death occurs at time t if depending on current health (whether it’s above some minimum level) and health during previous three periods (whether the average of those three periods is above a minimum level, with some randomness included).

Maternal Mortality
In the absence of a clinic, mothers die in childbirth 5% of the time. With a clinic present, they die in childbirth 1% of the time.

Demography and Malaria Epidemic:
Throughout the game, the S-I-R model below governs the demographics of the village population. The b and d constants (birth and death rates) control the basic population growth of the village, which is affected by the mortality (m) due to malaria. Note that the S-I-R model has no R (recovered population) because the disease in question is malaria, and a recovered individual immediately returns to the susceptible population. The mortality rate of the disease is a function of the village health level; the recovery rate is a function of whether there is a village in the clinic; the infection rate is a function of the precipitation level (rains can trigger an epidemic) and the number of bednets in the village. The system affects the player’s family via the malaria function above: the probability of anyone getting sick increases with a higher infection rate and a higher proportion of people infected.

Small Business
The income a person gains from engaging in small business depends on the person’s productivity (including whether there is electricity), how much effort (in man-hours) is spent in business, how prosperous the other villagers are at the moment (proxied by how the year’s precipitation compares with average precipitation and whether there is an epidemic underway), the extent of the market (proxied by whether there is a road), and how much capital (e.g. machines) is invested in the business. Capital depreciates at a slow rate of 2%.

Microfinance Unit:
Players can choose to take loans from and give loans to the microfinance unit. When a player chooses to borrow, an interest rate is offered based on whether there is a drought or epidemic underway. The maximum amount that can be borrowed depends on how much capital the person has in small business. After you borrow, you begin to pay installments on every turn (with total payback scheduled to happen in 4 years – 8 turns). If you don’t have enough money to pay your installment, then some of your business capital is taken away.

Note: Interest rate offered to people who are making loans to the bank varies from turn to turn. However, if you take out a loan from the bank, the interest rate at the time of the loan is the same interest you will face throughout repayment period.

You can only take out one loan at a time.

Achievement Points
Points are given for the average health of the family, the amount of money the family has in personal savings and as a balance in the community pool, the dollar value of each of the family improvements, and the dollar value of each of the village improvements.

Household Investments
Improved Wood Stove
Propane Stove
Propane Tank
Bednets
High-yield seeds
Fertilizer
Boat
Dragnet
Medicine

Taxation and the Village Fund
Villagers tax themselves at a rate set by the chief (determined by the player). You can choose to have no tax rate, or to tax some percentage of income (agriculture, fish, charcoal, and artisanwork) beyond what is needed for subsistence. That is, the part of produce that is required for subsistence is not subject to tax.

Tax revenues are collected in a Village Fund for the chief and villagers to draw upon for Village Investments.

Village Investments
Village investments are decided upon by the village chief, who meets with the villagers periodically to make decisions. The villagers can choose to make the following village investments:

Schools meals
Connection to power grid
Road
Clinic
Latrines
Irrigation
Water pump
Mass distribution of bednets

These investments can be paid for from the Village Fund. If the Fund cannot pay for the entire investment, then the villagers can choose to pay for the remaining balance during that turn, dividing it equally among all families.

Available Village Policies
Fishing quota
Fuelwood quota