# Questions tagged [beta-regression]

Beta regression is useful when the dependent variable is bounded, or when it has a ceiling or floor effect. It can also be used for modeling both the mean and the variance.

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### Logit GLM and logit beta regression: Practical difference in the interpretation of the coefficients?

Terminology: By logit GLM I mean a generalized linear model with a binomial distribution and a logit link function. By beta regression I mean beta regression with a logit link function. I understand – ...
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### Proportion data with number of trials known (and separation?): GLM or beta regression?

I perform a lot of bioassays in which I score mortality not on individuals, but on groups of individuals as a proportion (the denominator, i.e., number of trials, is known): Sample Data: ...
197 views

### Beta regression shows a weird plot

I am trying to model the relationship between my response 'crop coverage [%]' ~ weed coverage [%] + Soil Moisture [%] using R. Since I am dealing with proportions, I chose to do a beta regression. ...
81 views

### Differing confidence intervals between ggpredict() and ggemmeans() when REML = TRUE in glmmTMB beta regression

I am using the package ggeffects to estimate marginal effects and confidence intervals for a beta regression model fit with glmmTMB. I notice the estimates differ ...
49 views

### Beta regression using categorical variables

I have been asked to do beta-regression for my data. The independent variable is categorical (there are three treatments A, B and C). The dependent variable is the proportion of time an animal is ...
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### Can beta regression be used with continuous numerical data?

I am trying to fit a generalized linear model with Gamma distribution in R, but when I examine the residuals they are not normally distributed. I have a continuous numerical response variable, ...
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### How do I write out the components of my beta regression, and how do I interpret them afterwards?

I am estimating a beta-regression using the logit-link function with a continuous dependent variable bound between 0 and 1 and 5 continuous predictor variables. In R the equation is given by: betareg(...
73 views

### Why are predictions from beta regression and linear regression identical?

I'm utilizing a beta regression to predict the relationship between x and y, since y is a proportion variable confined within the interval [0,1] but has no values of either 0 or 1. Outcomes on y only ...
533 views

### Why does my beta regression look linear when plotted?

Im using a beta regression to model since my dependent variable is confined between [0,1]. However, when I plot the relationship between x and y via my beta regression, the effect looks linear. When ...
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### Beta-regression allowing for correlation of the error terms

I have a problem with beta-regression. In R exist a package "systemfit" that allows fitting regression (normal with identity link function) allowing for correlation of error terms. Anyone ...
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### Fitting a beta mixed model

I would like some clarification on fitting a beta mixed model. My dependent variable is the proportion of days that patients take medication. For every patient(Patient.ID), the pharmacy either had an ...
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### Selecting a betareg model out of all possible combinations of the EVs

I'm working on a dataset with response variable in [0,1] and n=61 observations, and trying to fit a model with betareg(). After posting my former question, I ...
114 views

### Appropriate Regression Model for Proportions and Rate Data

I have a problem where my dependent variable is given as a click-through rate and thus bounded [0,1]. While I have the traffic for each sample (a combination of design factors) and could reconstruct a ...
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### Calculating different pseudo-$R^2$ for a betareg model

Sorry if this is a bit long.. I've been trying to fit models predicting the % of area infested in a field (response between 0 and 100%, total of 61 fields), with four explanatory variables, two ...
1 vote
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### How can I calculate a beta regression prediction from the coefficients?

I have applied the R betareg function to my data using the default logit link and phi precision log-link for the categorical data. My equation is: ...
1 vote
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### GAMM with BETAR(Link = "Logit") [closed]

I'm trying to use betar in gamm4 models but keep hitting an error. As far as I can tell, betar is one of the families that should be available - can anyone identify why I would keep hitting this error?...
1 vote
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### Beta regression for ratio of counts

I have a question about whether it is appropriate to use beta regression when the proportion is formed as a ratio of counts. I have seen information suggesting it is fine and others pointing out that ...
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### Predict gamlss one-inflated beta model

How do you obtain predicted probabilities for the one-inflated component (nu model) of a one-inflated beta regression in gamlss? I have built the following model <...
171 views

### Interpretation of zero-inflated beta regression

I have constructed a zero-inflated beta regression model in gamlss. I find the output of this model somewhat confusing to interpret and was hoping that someone may ...
54 views

### Proper regression for my dataset - Zero-inflated beta regression?

I'm a bit stumped on the regression that I should be using for my dataset. There seems to be a general trend that as distance to a location decreases, the percentage of red material increases (as a ...
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### Bayesian Beta regression with random effects in R

Does anyone know of an R package that does (Bayesian) Beta regression with random effects? We know of Bayesianbetareg but this doesn't include random effects so I'm ...
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### Setting priors for a beta distribution in R-INLA

I'm running a regression in R-INLA, where the response variable is proportion of grid squares suffering deforestation (by year, over a 20-year period). Setting the response for the last 5 years to NA ...
1 vote
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### meanBEINF vs predict(model, type = "response') in BEINF GAMLSS. and determining odds of predictor variable coefficient

A variation of this question has been asked, but certain items remain unanswered - I am modeling the proportion of mortality (Prop) using a single continuous predictor variable which is temperature (...
610 views

### Beta regression: how to interpret the p-value of the phi coefficient

I am applying a beta regression to my proportion data (breeding success). My Phi coefficients show a p value of 0.043, which seems considerably higher to most examples I have looked at. I fail to find ...
277 views

### Zero Inflated Beta Regression

How can we check that the proportions are inflated at zero and one while using Beta Regression?
1 vote
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### How to correctly specify and diagnose one-inflated beta regression mixed-models (using GAMLSS)

I would like to find out what variables influence/explain an efficiency score for an invasive species control method. As the score is defined on (0,1] and as some observations were not independent, I ...
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### Choice of statistical testing - under five mortality rate

I am not sure if this question or similar one has been asked before but I have checked and to the best of my knowledge couldn't find a suitable answer. Here is my confusion: I have a dataset with ...
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### Structural Equation Modeling (SEM) with betareg in R

We have an SEM model and we were using Lavaan but we learned that the distribution of the residuals of one of the regressions is far from normal. The response variable in that equation is students' ...
223 views

### Interpreting interactions in beta regression

Edit I am using a log link and log(statemb) because my specific goal is to be able to conclude for small changes, an 1% increase in ...
1 vote
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### Time series proportion/share modelling issue

I want to model import share (one commodity product in country) as dependent variable from local price premium (local price minus import price) and seasonality factor (0 or 1). Model is used to make ...
360 views

### Which link function could be used for a glm where the response is per cent (0 - 100%)?

I am thinking about building a model (glm) where the response variable (y) is the cover (in per cent) of a plant species in a defined area, dependant of environmental variables. However, I don't think ...
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### Estimating proportion from aggregate data using regression

I am trying to estimate if a certain product is purchased by certain race(s) more than other. To do so, we have the following aggregate data Zip_code Percentage_of_buyers Asian_% Black_% Hispanic_% ...
1 vote
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### Relationship between quasi-likelihood and "GLM-conjugate" models?

Suppose we have a response variable that represents proportions with a poorly defined denominator. Two ways to handle this (1) a quasibinomial model, which assumes only that the variance is ...
1 vote
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### How to deal with negative proportions in Dirichlet Regression

I am trying to work on a Dirichlet regression problem where I look at three true proportions the first two are actually measured while the third is computed as the complement: $$p_3=1-p_1-p_2$$ The ...
298 views

### Beta regression fitted values

I have a beta regression model in R, have generated predicted (fitted) values based on my data, and plotted lines of those fitted values on a scatter plot of the actual data. I'm most used to GLMMs, ...
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### Beta regression and post hoc test correct linear connectors?

I am trying to run a beta regression on my percent data which can be found here. My research question: How is percent cover changing in each transect over each event? Beta regression was choosen based ...
202 views

### Is a beta regression appropriate for a skewed bounded continuous dependent variable when sample size is small?

My data contain a bounded continuous variable (score between 0 and 10) representing the efficacy of a given method to control an invasive species. As there are more high scores than low ones, the ...
1 vote
243 views

### GLMMadaptive - Hessian matrix problem Hurdle Beta Model

Data: I have a percentage (or proportion see paragraph below) outcome dataset with a high number of zero's. I have therefore attempted to run a hurdle beta model using the GLMMadaptive package in R. I ...
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### Improving fit of underdispered beta regression model in glmmtmb

I have survey data where the outcome is the proportion of a research budget interviewees wished to assign to one of three different "types" of research into solutions for various issues. I ...
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### Which regression model distribution or transformation for data bounded between -1 and 1?

It seems quite common in studies of plant interactions to find response variables that are bounded between -1 and 1, such as this relative interaction index (from Armas et al 2004, Ecology 85, https://...
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### Is there an R package that runs frequentist zero-one inflated beta models? [closed]

I have a set of proportion data (below) with a many 1s. I would like to run a one inflated beta model in R, and want to use frequentest statistics. However the only zero-one inflated beta package I ...
1k views

### Why is betareg() giving "invalid dependent variable" error?

I am trying to run a beta regression using the betareg package and I am using the following script: ...
170 views

### Accounting for Spatial Autocorrelation in a GAM: including coordinates of points as smooth terms is not working

I have been trying to use GAM/GAMMs to account for spatial autocorrelation in residuals of a GLMM. I have explained my data in detail in this Stack Exchange question. The question also demonsrates how ...
1 vote
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### Difference between t-test on betas from individual regressions vs linear mixed modeling

I often come across the following practice in my field; for example, people want to predict participants responses on a Dependent variable (e.g 0 or 1) based on a few independent variables - ...
1 vote
332 views

### Beta regression: Monte Carlo simulations for coefficients

I use betareg betaregresion to model degradation percentage over time: perc_degr~time. To calculate half-life (assuming logit ...
1 vote
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### How can I calculate standardized weighted residuals 2 for a beta family glmm in R?

Hello and thank you for your time! I’m trying to calculate the "sweighted2" residuals for a beta family glmm with varying dispersion (aka precision parameter aka phi) fit using glmmTMB in R. ...
334 views

### Modelling zero-inflated percentage data (vegetation cover) from single predictor variable

I am quite new to regression in R. I would like to analyse the relationship between 'Vegetation Cover'(response variable) and a single predictor variable 'Canopy Openness'. 'Vegetation Cover' is a ...
1 vote
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### Correct distribution to model proportion of time in a day

I would like to determine how the presence of researchers influenced the amount of time that shorebirds spent on the nest in a day. My data consists of proportions that range from 0.715-0.997, which ...