# Questions tagged [zero-inflation]

Excessive 0's in a variable compared to a specified reference distribution. Regression approaches include zero-inflated models and hurdle (2-part) models. For count data, zero-inflated and hurdle models based on Poisson or negative binomial distributions are common (ZIP/ZINB and HP/HNB).

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### Zero-inflation with sklearn and continuous target?

My current data have quite a large amount of zeros (~60%), and I'm thinking of trying to implement a zero-inflated model of sorts with sklearn. While I've used zero-inflated poisson/negative binomial ...
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### Interpretation of zero-one-inflated beta models in brms

I have 20 participants who have watched 18 clips. Every clip belongs to one category of pleasure (p_cat: negative, neutral, positive) and one category of intensity (i_cat: low, medium, high). I have 2 ...
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### Zero inflated and hurdle models - is it common do 'build your own' with e.g. ensemble model?

I have been given a new analytics problem to solve. The context is app analytics where we would like to predict total revenue per app install after 30 days from install based on just 7 days of data. I....
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### Gibbs sampling deriving complete conditionals with mixture priors

My question is about the derivation of the complete conditionals for Gibbs sampling in a hierarchical model where some of the parameters are mixtures of point-masses and Normal distributions. The ...
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### Basic idea of zero inflated two part models(hurdel) and application to big data (machine learning)

I'm currently working on the data which has 90% 0s in response variable. Based on my research, it seems zero inflated models could be a solution to this. However, while I was reading related documents,...
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### How to deal with zero-inflated proportional data in GLMM?

I have proportional data, i.e. number of individuals out of 6 that choose a certain option in a multiple choice experiment, so there are just 7 possible outcomes for each option: 0/6; 1/6; 2/6; 3/6; 4/...
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### Overall p-value for zero-inflated beta regression mixed model

I am analysing vegetation percentage cover data from grazed and ungrazed plots in R using a zero-inflated beta regression in package gamlss. Here are some example ...
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### Network architecture to predict zero-inflated output

I have a dataset of debt collections and I am trying to predict how much each person paid. The paid amounts are greatly zero-inflated. In the past I have built a two-stage model predicting the ...
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### What do the outputs of my zero inflated poisson model mean? (counts of fish)

I am looking a counts of fish within different size classes (0-10, 10-20 etc) between 3 different reef sites, 3 different depths and 2 different survey methods. However, naturally on all observations ...
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Suppose I want to do bayesian inference on the regression problem $\beta$ for Y = X$\beta$ + $\epsilon$ for $\epsilon_i \sim N(0,\sigma^2)$. The complication is that the prior for each component $\... • 1,407 4 votes 0 answers 1k views ### Fitting gamma distribution to data set with one zero observation I am using maximum likelihood estimation to fit a gamma distribution to shelf life data. Specifically, the data I have is the time (in days) between the day a product was sold and the day the first ... 4 votes 0 answers 10k views ### Fitting a zero-inflated negative binomial regression with R In this thread, I laid out a problem involving fitting a model that attempts to use minor league baseball statistics to predict success at the major league level (explained in full in the thread). ... • 869 3 votes 0 answers 33 views ### How do zero values affect the correlation between two twitter activity time series? I have a time series of Twitter activities (lets call it time series 0) from which I extract two separate time series based on different sets of users (i.e. time series 1 contains the activity of a ... 3 votes 0 answers 90 views ### Difference between running a zero-truncated model on zero-truncated data and running a GLM on zero-truncated data I apologize if this a remedial question but I am trying to determine how best to proceed with my analysis and I would appreciate if someone could explain the differences in assumptions between a zero-... • 31 3 votes 0 answers 85 views ### Explanatory model for zero-one inflated bimodal data with random effect and binary indepentent variable I'm trying to evaluate the influence of a single binary explanatory variable on a 0-1 scale response, with one grouping factor. The response variable is generally 0-1 inflated. The simplest solution ... 3 votes 0 answers 696 views ### Interpreting zero-inflated Poisson regression I fitted a zero-inflated Poisson regression with "group" (4 groups in total) as indepentdent variable and nchoice (frequency that a person choose a certain answer) as dependent variable. I ... 3 votes 0 answers 409 views ### Zero-inflated negative binomial model standard error too high? I've been trying to analyze count data for ant foragers visiting on extrafloral nectaries with R. My data is both overdispersed and zero-inflated, so I used a zero-inflated negative binomial model to ... 3 votes 0 answers 683 views ### Multivariate zero_one_inflated_beta regression I want to run a zero_one_inflated_beta regression with brms on the following multivariate formula: ... • 105 3 votes 0 answers 1k views ### How to conduct a principal component analysis on data set with large number of zeros I have data for percentage cover of plant species in 500 sites. There are columns for 30 different species in the data set and I would like to drastically reduce this down to a manageable number of ... • 293 3 votes 0 answers 234 views ### Do zero-inflated models induce selection bias? Zero-inflated models (e.g., ZI poisson, ZI negative binomial, hurdle) assume two processes for the generation of the observed outcome variable: a process for deciding whether the outcome is zero or ... • 35.2k 3 votes 1 answer 204 views ### Contradiction between zero-inflated poisson model coefficients and graph of the model? EDIT: Added an reproducible example For one of my models, it seems the coefficients and the graphed out model do not agree. I'm working with adverse effects data, in which intense reactions are rare ... • 31 3 votes 0 answers 925 views ### High proportion of zero values and PCA My aim is to perform PCA since I have 76 variables in my dataset. Problem is that most of my variables are highly skewed as you can see in the histogram below. These variables are proportions derived ... • 41 3 votes 0 answers 503 views ### How to specify a zero-inflated Dirichlet model in JAGS/BUGS There was a recent publication discussing the advantages of the zero-inflated dirichlet for microbiome count data which is compositional (you are modeling a matrix of species relative abundance data ... • 1,242 3 votes 0 answers 2k views ### Negative binomial model vs zero-inflated negative binomial - theoretical justifications I have a count variable that I would like to predict using a categorical variable (it has 4 levels). I would like to decide whether I should use Poisson, negative binomial, or zero-inflated negative ... • 305 3 votes 0 answers 2k views ### How to handle Zeros in dependent variable in Multiple Linear regression I am totally new to machine learning (and to this platform too) and was trying to implement Multiple linear Regression to improve my ranking algorithm. I have a data-set which have the following ... 3 votes 0 answers 4k views ### Distribution with zeros that is lognormal without zeros I have 79 observations with 30 as first quartile, 50 as median, 50.5 as mean, 68 as third quartile. Max value at 169, min value at zero. In particular there are only 4 observations at zero. The ... • 31 3 votes 0 answers 583 views ### Measure of relationship between two variables that are percentages containing many zeros I am working with various different data sets (in the context of forest reclamation on industrial disturbed landscapes) that contain percent cover values of desired (planted) and undesired plant ... • 6,521 3 votes 0 answers 85 views ### Fitting zero inflated right truncated negative binomial distribution I have a dataset that is bounded above by 2000 (physically not possible to have larger than 2000 values). Is there a way, in R, to fit a zero inflated, upper bounded negative binomial distribution to ... 3 votes 0 answers 286 views ### Weird beta inflated distribution qq plot (easy reproducible code included) First, I do this library(gamlss) simnorm <- rnorm(1000, 0.5,0.1) simzero <- rep(0,1000) x <- sample(c(simnorm,simzero),1000, replace = TRUE) which ... • 31 3 votes 0 answers 508 views ### Negative binomial regression - only for count data? I've been pouring over statistics blogs over the last couple days to find a satisfactory answer to this, but I can't seem to find one, so I'll pose it to you in hope of a quick fix. Basically, I'm ... 3 votes 0 answers 2k views ### What is Mu in zero/one beta inflated models? (gamlss (BEINF)) I am estimating a zero/one inflated beta regression model with gamlss (family BEINF). My dependent variable is [0,1] with a lot of 0s, quite some 1s, and some values in between. This means I assume ... • 163 3 votes 0 answers 404 views ### Traceplots and gelman.rubin statistics for analysing convergence of mixtures of discrete and continuous distributions I have a Bayesian hierarchical model which contains a number of distributions which are mixtures of a point-mass at zero and a continuous random variable. The model is fitted using a gibbs sampler. ... • 479 3 votes 0 answers 412 views ### How to interpret conflicting results between the binomial and count part of a Zero-Inflated Poisson model? In my model one of my variables (X2 below) is significant and has a negative sign in both the binomial and count parts of a ZIP model. I was wondering how to ... • 555 3 votes 0 answers 879 views ### glmmADMB- Pseudo R^2 and residual deviance criteria I’ve been using glmmADMB to fit zero-inflated negative binomial models with a random effect (as far as I can tell, this is the only package that will allow me to do this). I have been trying to do ... 3 votes 0 answers 823 views ### Zero-inflated GLMM: correct use of AIC and comparing levels of fixed factor I am struggling with a ZIGLMM in R. I have a data set on freshwater plant propagules (response variable) and the relation with the ecological state of ponds. Pond state is a categorical factor with ... • 31 3 votes 0 answers 1k views ### How to Test for Some Basic Assumptions of (Zero Inflated) Negative Binomial? I am currently working with a T dominant panel --time-series cross-section dataset-- that has N = 8 (eight European countries) and T = 28 (28 quarters for each country). The dependent variable --... • 141 3 votes 0 answers 845 views ### Double Hurdle model with continuous DV and two sources of zeros I want to regress a data set that contains a lot of zero's (~55%) and is determined by a typical 2-stage decision process generating the zeros: Consumer decides to apply for a bank loan or not (0-1) ... • 370 3 votes 0 answers 32 views ### Estimating proportion of region cropped by proportions in random samples I have a series of quadrats placed randomly across aerial photography of a region. In each quadrat I have estimated the proportion of the quadrat under cropping and my goal is to estimate the ... 3 votes 0 answers 2k views ### Zero-and-one inflated beta regression vs. binomial GLMM? I appreciate some help with deciding whether I should (and how to) construct a zero-and-one-inflated beta regression model. I want to use R to test the hypothesis that there is a ... • 31 3 votes 0 answers 193 views ### Appropriate test (in R) for proportion data that aren't normally distributed, aren't based on counts, and include 0's and 1's? I'm studying differences in tree health among 5 species of trees across 3 different green infrastructure types. Here are the first few lines of data: ... • 31 3 votes 0 answers 318 views ### Count data with one factor level containing only zeroes I have a simple poisson glm with one predictor that has three levels. Unfortunately, for one level my response, the variable has only counts of zero. I expected very low counts (perhaps a one or a two ... 3 votes 0 answers 1k views ### Suitable method for modelling (underdispersed?) count data with lots of zeros and long tail I have a small data set of counts of bees. I tried a simple Poisson model without random effects but it was very overdispersed (3.95). When I fit a GLMM with random effects (using glmer in lme4) it ... • 161 3 votes 0 answers 74 views ### How to model continuous predictor variable,$x\ge0$, showing continuity "jump" at$x=0\$?

I'm modeling hospital inpatient stays with a logistic regression model, and have encountered a number of predictor variables measuring # of outpatient care episodes which have an inflated number of ...
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### Mixed models and normally distributed random effects

I am attempting to analyze some data that includes 10 repeated measurements on 10 different samples. This would normally require using mixed models, and I have attempted to model these using ...
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### Is there a distribution appropriate for a continuous variable skewed toward zero and able to include zero?

I am interested in modelling the impact of some environmental parameters on a concentration of measured phytoplankton pigment. The concentration of pigment is skewed so that low concentrations are ...
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### Zero-inflated Poisson - Implementing INLA with two likelihoods

I am trying to implement a zero inflated model in INLA. I know a basic zero inflated Poisson can be implemented with "zeroinflatedpoisson1" as the family ...
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### Hurdle model for non-count continuous data with both positive and negative values

I am aiming to estimate a hurdle model (where being non-zero is the hurdle) in the vein of Cragg. My data is both positive and negative where the data reflects the difference between a value reported ...
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### Zero inflated dependent variable and tree ml regression models

I wonder, if tree based ml models (e.g. xgb or random forests) are actually susceptible to zero inflated dependent variables (DVs) in the case of regression (in a sense the DV is at least bi-modal)? ...
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### Interpretation of ZINB when ziformula = ~1 in glmmTMB

I estimated a ZINB model with the probability of producing a structural zero as equal for all observations with ziformula = ~1. For context: I want to know what predicts the number of cigarettes ...
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### Mann-Whitney U Test test valid for percentages (% seagrass cover)?

Is the Mann-Whitney U Test test valid for percentages (not counts, but percent cover of seagrass)? All my data points are average percent cover of seagrass with about 53% of the data being zeros ...
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