# same_age_bias

Mixing group property that influences the tendency of agents of similar age to interact

## Synopsis

same_age_bias = <number>


## Description

This mixing group property influences the tendency of agents of similar age to interact.

To set the same age bias for a mixing group type, the definition of the type may include the following properties:

place <place-name> {
same_age_bias_prob = <number>
same_age_bias_for_<condition_name> = <number>
}

network <network-name> {
same_age_bias_prob = <number>
same_age_bias_for_<condition_name> = <number>
}


The first property specifies the same_age_bias for all conditions. If a property of the second form occurs, it overrides the first property for the named Condition.

Negative values for same_age_bias are ignored. A value of 0 results in no age bias. If the place has a positive age-bias, the bias is computed by the formula:

$$same-age-bias(source, target) = exp(-(same_age_bias of group)*(|age_of_source - age_of_target|))$$

That is, the probability of transmission decreases with a larger difference in age between the interacting agents.

## Parameters

• numberfloat

Value of same age bias.

## Notes

There is also a simulation property that enables transmission in place to take age-bias into account, and it is enabled by default:

simulation {
enable_transmission_bias = 1
}


## Examples

The same age bias can be set to 2 for a user-defined place type called Mall with:

place Mall {
same_age_bias = 2
}