[statnet_help] Examples of dynamic population equilibria with
more than two groups in EpiModel stochastic network models
morrism at uw.edu
Sat Oct 31 12:46:22 PDT 2020
Hi Benji -- you should post this on the EpiModel listserv.
On Sat, 31 Oct 2020, b wrote:
> I am trying to incorporate custom arrival and departure modules into a network model (SEIRQ) with 4 different "types" of
> individuals (still in v1.8). The context interprets "arrivals" and "departures" as replacements for each other from a
> fixed reservoir, without actual deletion of these nodes as in the mortality module. The total N is fixed. When one
> "departs", they can no longer form partnerships, and an arrival of the same type replaces that individual, until a few
> time steps later, when the exchange happens again. How many time steps later is determined by the type, and each of the 4
> types has unique durations to remain in and out of the network (mimicking their work schedule, independent of status). I
> am having difficulty coding this population to maintain a dynamic equilibrium. It would be easier in a .icm with 2 groups
> or types that each arrived for X days, then departed for X days, with all the rates balancing.
> Surprisingly, I haven't been able to find any examples in the literature of EpiModel network models using
> (non-birth/death) arrival and departure modules with a fixed population. If you can point me in the direction of an
> example, it would be very instructive to see how dynamic equilibrium is coded into a network model with more than two
> groups when you can't simply calibrate birth and death rates to equilibrium.
> Benji Zusman
> University of Florida
> On Mon, Oct 12, 2020, 3:02 PM <statnet_help-request at mailman13.u.washington.edu> wrote:
> Send statnet_help mailing list submissions to
> statnet_help at u.washington.edu
> To subscribe or unsubscribe via the World Wide Web, visit
> or, via email, send a message with subject or body 'help' to
> statnet_help-request at mailman13.u.washington.edu
> You can reach the person managing the list at
> statnet_help-owner at mailman13.u.washington.edu
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of statnet_help digest..."
> Today's Topics:
> 1. How does ERGMs deal with parameters that cannot be estimated
> from the data? (David Kretschmer)
> ---------- Forwarded message ----------
> From: David Kretschmer <dkretsch at mail.uni-mannheim.de>
> To: statnet_help at u.washington.edu
> Date: Mon, 12 Oct 2020 17:23:17 +0200
> Subject: [statnet_help] How does ERGMs deal with parameters that cannot be estimated from the data?
> Hello dear list users,
> I estimate an ERGM that includes a parameter that cannot be estimated from the data, i.e., it contains a dyadic
> covariate that has the value zero for each dyad.
> To my surprise, running an ERGM on this data does still provide a coefficient estimate for the parameter that
> cannot be estimated from the data. Under normal conditions, the coefficient estimate is zero, and the standard
> error and all other elements in the ERGM output are NA. Still, I wondered why a coefficient value of zero is
> reported even though the parameter clearly cannot be estimated from the data.
> Furthermore, when using the “constraints” argument of ERGM (constraints = ~bd(maxout = 5) in my case), the reported
> coefficient estimate is no longer zero but some other, seemingly random value that frequently is very high (e.g. 51
> in one example run). Here, I also wonder how the ERGM arrives at this value.
> In general, it is clear to me that these coefficient estimates are without substantive meaning. However, I wonder
> why they are still reported in the ERGM output and how the corresponding values come about.
> Any help would be greatly appreciated.
> David Kretschmer
> Universität Mannheim
> Mannheimer Zentrum für Europäische Sozialforschung (MZES)
> A5, 6
> 68159 Mannheim
> Tel.: +49-621-181-2024
> statnet_help mailing list
> statnet_help at mailman13.u.washington.edu
Professor Emerita of Sociology and Statistics
University of Washington
Seattle, WA 98195-4322
Office: (206) 685-3402
Dept Office: (206) 543-5882, 543-7237
Fax: (206) 685-7419
morrism at u.washington.edu
More information about the statnet_help