so now we have a basic idea of what we
want our model to look like right uh and
what we want to get out of it so now we
need to think about how are you actually
going to build that model right and
right here I have laid out seven design
choices you need to make when
constructing an agent based model right
uh and you know the these kind of go
take you through step by step thinking
about what that model is going to look
like so the first one is what part of
your Phenom what you like to build a
model of uh this is kind of asking the
scope SL question question right um and
then what are the principal types of
Agents involve what properties do these
agents have what actions or behaviors
can these agents take how do these
agents interact with each other or with
the environment and what kind of
environment do these agents operate are
there as we call them Environmental
agents agents that actually take action
but may not be moving or may place an
environments around the other agents um
and if you had to define the phenomena
as the scre time steps what events will
occur in each time step in what order
and what do you have to hope to observe
in this model and if you think about it
this is similar to the questionnaire I
had you fill out early on where we
actually spent some time uh thinking
through these for a model you're
interested in building right so let's
talk about each of these in detail so
scope and question well before any
design any concrete design decisions are
made you should make sure that it makes
sense to model your question using ajb
modeling uh and of course we went over
that in unit one as to what the
different advantages are of using ad
base modeling and given that you might
want to refine the original research
question that you had in light of these
advantages so if we think back to the
information diffusion question and we
think about what aspects of it really
allow h of Bas modeling to shine well
one of them is you know heterogeneity of
individuals right that was something we
talked about and individuals in the
network diffusion question or in the
infusion diffusion question have
heterogeneous positions within the
overall social network and that could be
something that we we want to think about
right um agents might also have local
but complex interactions right if you
think to the bass model right the the
decision to adopt or not adopt once we
move to a network context it's not based
upon some sort of aggregate level
statistics but it's based upon my locals
at level of who's adopted which is a
local interaction that's potentially
complex and we can think of other
adoption roles that might be even more
complex in that one as we'll discuss
later um it's also the case that the
environment is very rich right and as a
result some agents may have more
information sources than others they may
be hubs they may uh might be potentially
affected by their Network structure so
given all that let's rephrase our
original research question to be
something along lines of how does novel
information diffused through a
population embedded in a social network
based on both broadcast and local
information
drivers so the second thing you want to
consider is what are the Agents of your
model and tied up with this is the
granularity SL level of the agent so
this is dealing with at what scale are
we going to model our agents right um
are we going to do it at a cellular
level at an organization level or as was
commonly done the individual human level
right and this is partially related to
the temporal scale question right are we
interested in how much information a
person adopts tomorrow or are we
interested in how much information
organization doops over the course of
its entire uh over a year for instance
right you might also at this point start
to think about Proto agents so certain
things you might initially think well
that can make that needs to be an agent
in my model right so in the case of the
diffusion question maybe broadcast media
like the TV um any even the internet for
that matter need to be represented as
agents but maybe they don't because at
least initially we're not going to
really give them their own properties
they're not going to respond to what the
consumers are watching at least in our
model because we're not interested in
the consumption model we're interested
in the defusion model right so these
might be what we call Proto agents right
uh so in the diffusion example I can
think of at least three types of agents
that we have we have human individuals
right uh we have network connections
which are agents themselves right the
social connection between two
individuals could be an agent uh because
it might have its own properties it's
like weight and confidence and things
like that and the media the broadcast
media we
talked interestingly enough human
individuals might have different types
as well right so we might have some
agents who are really experts in their
field right and have more ability to
influence others uh than the non-experts
uh and so as a result of that we might
think about multiple types and in the
traditional diffusion literature there's
often a discussion about what they're
called influential agents versus
imitator agents and so maybe we can
think about them from that context