Questions about BUGS language for defining Bayesian models that can be run by the WinBUGS software package. It is advised to supplement your question with a reproducible BUGS example (http://stackoverflow.com/q/5963269).

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8 views

How can I calulate predicted mean of variable x1 from this model

Final Analysis of BDHS model ...
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29 views

Expected value of inverse-Wishart prior in JAGS

I am trying to estimate a covariance matrix in JAGS, using a prior centered around the expected variances. Thus, I want to assign a prior with expected variances that are about equal to the observed ...
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34 views

How to calculate MSPE in winbugs when I use Zero Inflated Poisson regression?

I have had question about Winbugs code. I used ZIP(Zero Inflated Poisson) regression code in winbugs, and I want to compare two models(Poisson Model and ZIP model) using MSPE(Mean Square Predict Error)...
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27 views

Change a random effects model into a fixed effects model in *BUGS

I want to manipulate this RE model into a FE model for sensitivity analysis. The model is described here: Baseline natural history model ...
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176 views

Which is the best method for network meta-analysis?

There are now several different approaches to perform network meta-analysis. The most commonly used and accessible ones are probably the following: frequentist network meta-analysis with ...
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0answers
37 views

Mixture model: 3 binomial components (using WinBugs)

I've a BUGS question I've been unsuccessfully trying to define the likelihood for a mixture of 3 binomial distributions. I'd like to estimate the mixing proportions for a given dataset. Once this is ...
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24 views

Conditional statements in Winbugs

I am using Winbugs for bayesian estimation. I have a categorical data that consisted of the values:1,2,3. Here is what I have: ...
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98 views

Modeling quadratic function parameters as a function of variables

I'm modeling a response variable that varies seasonally. The pattern is relatively well described by a quadratic function. As the data have been collected over many (~50) years, I'm interested to ...
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0answers
90 views

WinBUGS - sample from the posterior of exponential distributed survival times

as introduction to WinBUGS, I want to simulate the posterior of the Gamma-Exp-Model. Because the posterior is known, I can varify the result. But the true posterior is always shifted to the right. I ...
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8 views

Expected count in Winbug

I have mortality count and total population of each counties of three states for 5 years. I want to get the expected count of mortality at each county and year to input in the Winbug. I wonder how ...
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1answer
152 views

Priors for Truncated Parameters - RJAGS

I would like to estimate the parameters of a specific model. The model specification is as follows: $p_t = k_t + B_t/(1-B_t) + \eta_t$, where $ \eta_t \sim N(0, \sigma^2)$ $R_{t+1} = R_{t} + R_t (...
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223 views

Bayesian modelling, measurement error & carrying-over posterior distributions

I have a (fairly convoluted, but well-inentioned) model in my head, and am trying to figure out if it's possible to code (I am currently getting to grips with R2WinBUGS). The final model is basically ...
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1answer
203 views

“Multiple definitions of node p[1]” Error using WinBUGS [closed]

I have written the following code in WinBUGS and every time I try to compile the data after loading in the data I get the same error which is "Multiple definitions of node ...
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0answers
189 views

code works in jags but not winbugs [closed]

I have band-recovery data from several areas, and am trying to get survival rates for adult and juvenile for each area. Brownie model is used. The model is: ...
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2answers
82 views

(Failure) probability calculation

I am working on mortality in 12 hospitals performing cardiac surgery in babies. The dataset is available here: Surg dataset. The dataset is structured in this way: ...
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0answers
29 views

OpenBUGS and coda library

I've fitted a hierarchical model with OpenBUGS using R2WinBUGS package of R. Now, I'd like to use the functions contained in the ...
4
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1answer
98 views

Can improper priors be implemented in some way?

I'm new to bayesian inference. I've just discovered that improper priors can't be specified in WinBUGS/OpenBUGS. I was wondering if this is common or not in bayesian inference. Are there same cases ...
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159 views

Defining prior on variance and not precision

I know that WinBugs uses precision as a parameter in dnorm instead of variance ...
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1answer
120 views

Is multinomial the same as multiple binomial?

I wonder, if I write - in JAGS, WinBUGS, or in a paper: x[] ~ dmulti(p[], N) is it the same as if I write: ...
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1answer
170 views

How can regression trees be fit in WinBUGS/OpenBUGS/JAGS?

There is an R package called BayesTree which can fit regression trees in Bayesian environment. However, this way only simple regression is possible. I would like to use regression trees as a part of a ...
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1answer
136 views

WinBUGS: multiple definitions of node [duplicate]

I wrote this code in WinBUGS but I can't run it! It says 'multiple definitions of node tau' ...
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0answers
90 views

Confidence intervals of proportions for clustered data

I am trying to compute the proportion of "yes"'s in data that is clustered (participants within cities). If I ignore the cities, I get very nice and narrow confidence intervals. If I compute the ...
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1answer
1k views

Undefined real result error at WinBUGS

I am currently working on my thesis and interested in estimating a multilevel differential item functioning model and I using at WinBUGS. Until I had done model check-up, there are no errors. However, ...
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1answer
49 views

Measurements from two raters. Should I use multilevel/“random-effects” model?

I have several variables that were measured on patients, for most patients the variables of interest were measured by 2 independent "raters". Most of the variables are binary. I need to compute the ...
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364 views

Is my OpenBUGS / WinBUGS model well specified?

I've just started trying to use OpenBUGS for Bayesian analysis of stochastic volatility models. In particular, I'm trying to calculate stochastic covariance, similar to the DC-MSV model specified by ...
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778 views

What is the form of link function in this BUGS multinomial regression example?

The alligators example from openbugs examples repository is the same example that comes with winbugs. Basically this is a multinomial logistic regression example in which the outcome variable has 5 ...
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2answers
887 views

Bayesian estimation of $N$ of a binomial distribution

This question is a technical follow-up of this question. I have trouble understanding and replicating the model presented in Raftery (1988): Inference for the binomial $N$ parameter: a hierarchical ...
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0answers
114 views

Dawid Skene model for BUGS

I'm a beginner in BUGS. I'm trying to code the Dawid Skene model in BUGS. The model is as follows: Currently, I'm adapting the code from Stan, here. Here is the code: ...
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243 views

Longitudinal data format in WinBUGS or OpenBUGS, different number of items per time point

I am working with longitudinal data, where there are a different number of "items" per time point. I am working with the MCMCdynamicIRT1d function in ...
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96 views

WinBUGS multinomial all parameters are random variables

everyone here. I want to use multinomial distribution, but p[] and N are all random. model is correct and data loaded , model compilied, but it can't still run , it says:value of binomial f[1] must be ...
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323 views

Zero trick in WinBUGS for truncation

I am using the Zero-trick to create a prior for correlation parameter. Data y is a bi-variate normal with covariance matrix with same diagonal elements and ...
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0answers
100 views

How are deterministic/logical nodes represented mathematically in directed graphical models?

Various software for performing inference on graphical models support logical(a.k.a deterministic) nodes. PyMc, Winbugs, Smile are the ones I'm aware of. Based on the different inference methods ...
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155 views

Multigroup Longitudinal Item Response WinBUGS OpenBUGS

I was able to fit the Longitudinal IRT model in Winbugs for an ordinal response by extending the BUGS code I took from the paper by Curtis in JSS http://www.jstatsoft.org/v36/c01/paper/ However, I am ...
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26 views

WinBUGS sript: display correlation [closed]

Does anybody know if it is possible to display the correlation matrix using WinBUGS script? (with the GUI it can be found in th Inference menu -> correlations -> print) Thank you everybody!
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714 views

Dummy coding from a Bayesian point of view

If we want to use categorical variables in regression context, we are allowed to use dummy codings such as these schemes. Is this also required in a Bayesian (MCMC) context, such as with WinBUGS/...
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68 views

Truncated normal in WinBUGS

I want to use the following truncated normal distribution in WinBUGS to estimate parameters of SEM using Bayesian analysis. ...
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92 views

Inverse normal distribution in winbugs

I want to use the inverse normal distribution in winbugs but I don't find it there. Please help me to find a solution. I have here truncated normal distribution for y ...
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2answers
325 views

Joint prior distributions in WinBUGS

Suppose we have a hierarchical model summarised by the following: $y_{i} \sim N(\mu_{i}, \sigma^{2})$, for $i = 1, \ldots, n$; (For these purposes, assume $\sigma^{2}$ is known) where $\mu_{i} = \...
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0answers
73 views

How to make WinBUGS close when “Trap” occurs [closed]

I'm using R2WinBUGS to process several datasets in WinBUGS in "batch mode". Occasionally traps occur, mainly due to bad parameters (I guess), and I managed to avoid ...
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0answers
2k views

WinBUGS/OpenBUGS Gamma distribution parameters [closed]

According to the WinBUGS manual the gamma distribution is defined by: dgamma(r,mu) However, what is r? Is it the shape, scale ...
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2answers
207 views

Specification of logical node (with distribution?) in WINBUGS

For a piece of homework I have an assignment using WINBUGS which I must admit confuses me to say the least. Tangential to my question but I have a few stochastic nodes that are to be gamma ...
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1answer
189 views

JAGS burn-in phase takes ZERO time? [duplicate]

My breath was taken away by this. I tried to run my JAGS model with different number burn-in samples but it still takes the same amout of time!! ...
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676 views

CAR spatial models in JAGS

WinBUGS comes with the GeoBUGS add-on, which contains a number of predefined model structures that are suitable for modelling spatial data structures e.g. geostatical structures (spatial.exp), ...
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1answer
433 views

Undefined real result in a zero-inflated negative binomial

I have run a zero-inflated Poisson model in WinBUGS without problems, and now I am trying to run its equivalent negative binomial. However, I get an "undefined real result" trap message over and over. ...
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1answer
936 views

Estimation of the shape parameter of gamma distribution in Winbugs

I want to estimate the shape parameter of gamma distribution in Winbugs. I select gamma distribution as prior for shape parameter. Data set is generated using MATLAB as: ...
3
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1answer
1k views

Define Priors for Dirichlet Distribution parameters in JAGS

I'm defining a Multinomial-Dirichlet model in JAGS and want to assign some hyperpriors to the parameters of the Dirichlet distribution. In the WinBugs manual I read that "the parameters of Dirichlet ...
2
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1answer
656 views

How can I estimate the precision of a normal using a Gibbs sampler?

I am trying to estimate the precision $\tau$ of a normal distribution with either WinBUGS or OpenBUGS: $c \sim \text{normal}(\mu,\tau)$ $\mu \rightarrow \lambda \cdot t^{-\beta}$ $\tau \sim \text{...
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0answers
294 views

The effective sample size from WinBUGS results

I am running a Bayesian regression model by WinGUBS via R2WinBUGS package in R. Everything looks fine except for one parameter: ...
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1answer
1k views

Trap 66 in WinBUGS in a hierarchical Bayesian modeling

I want to analyze a multilevel multidimensional model in WinBUGS. the model is as below (N=2362 students responding to K=45 items of a test, students are nested within J=116 schools): ...