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).

376 questions
Filter by
Sorted by
Tagged with
16 views

How to analyze data with unequal length of observations and many zeros?

I want to analyze the impact of the rain on smoking probability. I observed people in two cities on the streets and marked the following parameters: city, gender of the person, duration of observing ...
6 views

ZINB_ZIP model application [closed]

Under what conditions is zinb model better than the zip model? After selection model how can parameters be estimated? Recently I read a related article containing heterogeneous random effects that ...
14 views

How to obtain different values of “parameter k” in a mixed-effects negative binomial model?

I have a dataset with two level factors - fertilizers ("Nitrogen" or "Phosphorous") that differed in their concentration level("...
36 views

Poisson on frequency data with many 0, underestimated output

I have got a frequency table of how many events occur within a 5-minute time window. ...
37 views

Extracting the right summary statistics from zero-inflated data sets (i.e. a sparse matrix where everything non-zero is a statistical outlier)

I'm a consumer tech startup founder with rudimentary background in statistics. I need help in processing a large, sparse matrix. I'm logging all actions users are undertaking in my app. I then ...
36 views

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/...
36 views

Inferences from a zero-inflated negative binomial distribution?

Frogs are generally known to spatially aggregate during egg-laying. I manipulated their egg-laying sites with different fertilizers ("Nitrogen" or "Phosphorous") that differed in their concentration ("...
41 views

analysis of variance on zero inflated semi continuous data

I have a fairly fundamental problem with my data, they do not suggest that they were sampled from a normal distribution. This is problematic because I would like to run some sort of analysis of ...
13 views

What model is appropriate when a non-negative, continuous dependent variable has frequent zero-values because of limited data?

I'm modeling how likely a song is to occur in a playlist with a particular title. I can calculate a simple probability based on my current data, but it's highly zero-inflated because my data is ...
19 views

zero inflated interval data

looking at the survey my data set is based on, my dependent variable originally is given in percentage ranging from 0 to 100. Howewer, in my dataset the information is categorized in to 9 intervals. 0 ...
16 views

What is the impact of excess zeros on poisson regression coefficient estimates?

The background I have a dataset with some zeros - based on how I segment my data, it is either 50% of the observations or 80% of the observations. The data is not actually count data, but from what i ...
88 views

Variable selection in zero-inflation models

I am trying to understand how to perform model comparison between different count models. In this example the author performs a zero-inflated poisson model testing the effect of number of people in a ...
48 views

How to plot estimate + raw data of a Bayesian zero inflated poisson?

GENERAL QUESTION: How to back-transform estimates from a zero-inflated poisson to obtain the original scale in R? (I tried exponential like for poisson but the results are wrong) DETAILED ...
32 views

R - zero biased data, glmer.nb, properly counting confidence intervals

any suggestions how to count confidence intervals from zero biased data? I've counted generalized linear model using glmer.nb function. I have to make graph but I was told that confidence intervals ...
67 views

How to model a zero-inflated 'continuous' response data in r 'without' assuming an underlying normal distribution?

I have a weather data set with rainfall as response. It has 56% observations as 0, while the rest as continuous rainfall data. I can't use tobit, hurdle or any other zeroinfl() model as they require ...
21 views

How to calculate ICC for a zero-inflated negative binomial model

I did a zero-inflated negative binomial regression on some data. However, the data is nested (students within schools), and I would like to calculate ICC to make sure that we did not need to take this ...
9 views

How to optimize statistical approach in terms of reducing number of statistical tests used?

I need to analyse second step care among very heterogenic patient population whose second step care is also very diverse. I can do this using multiple models and tests (up to 10), but this is just too ...
50 views

Approach to Analyzing Semi-Rare Events

I am often faced with analyzing data that follow a pattern as shown in a mock example in the image below. Key data characteristics: for any value of the predictor (e.g. temperature), the most ...
56 views

Hurdle model vs left censored model

When dealing with response variables that have lots and lots of zeros, is there a clear argument for when hurdle models are preferred and when left censored or tobit models are preferred?
34 views

What regression type for Normal DV and count data IV (with lots of 0s)

I'm performing regression on subjects' response to a question on a 1-5 likert scale (1=low, 5=high, etc)- This is the DV and its continuous and normally distributed. The IV is a count of how many ...
143 views

Model selection: Two-Part Mixed Effects Model for Semi-Continuous Data

I have now been studying mixed models for about a month, I am still a pure beginner. I have zero inflated semi continuous dependent variable (yield of trees between two periods). Exploring ...
48 views

How to interprete the p values of cos and sin terms in periodic regression?

I have camera trap data where for each site and hour I have the abundance of wild herbivores. I want to create a model where I can estimate the effect of predator activity on the activity and behavior ...
38 views

Choosing error function for regression

I have a dataset with ~100K samples and non-negative continuous target variable. 99% of target values are zeros and the remaining 1% are right-skewed. Here are the deciles (0 and 1 correspond to min ...
25 views

Extremely large (>10000) value of theta in hurdle model

I am estimating a hurdle model with a binomial (first stage) and truncated poisson distribution (second stage). The results look fine but I have a very large value of theta (greater than 10000). I ...
18 views

How to model zero-inflated mass data? [duplicate]

I am working with a data set of the mass of plastic found at various sites. At most sites, we found no plastic and so the data is zero-inflated (see histogram below). I want to model the data using ...
17 views

Zero-inflated Poisson regression with unit and time fixed effects (Application in R)

In much need of some assistance. My question concerns the conceptualization of zero-inflated Poisson regression in a two-way fixed-effects settings. I have crime data and my outcome is 'count' ...
34 views

Conflicting residual diagnostics for GLMM for binary data: zero-inflation

I fitted a mixed logit model with crossed random effects in lme4_1.1-21::glmer to some experimental binary data. The maximal random-effect structure justified by ...
18 views

Computational error for zeroinflated negative binomial regression model

I am trying to fit a zero-inflated neg. binomial model. I have many predictors for the count model, but only one for the zero model (Saturday). ...
17 views

Zero-inflated model with no variation in the outcome

I want to fit a zero-inflated neg. binomial model using zeronfl(outcol ~ vm + Thursday + Saturday |Saturday + Thursday + vm, data, family="negbin") from the pscl ...
60 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 ...
52 views

Which model should I use? (genomic problem)

I have problems with choosing which model / link function should I use for my analysis. My response: numbers from -100% to +500% (increase of tumor after therapy, may switch to ratios or log-ratios, ...
71 views

zero inflated presence absence binomial GAM in R

I am fitting a binomial GAM using mgcv in R. My data is presence (1)/ absence(0) of dolphin acoustic detections in 10 minute time windows over ~1 year period. However, I have only ~750 presences to ~...
117 views

DHARMa diagnostics: testDispersion and testZeroInflation interpretation

I have been analyzing count data using Poisson distribution in glmmTMB, and just ran some DHARMA diagnostics. However, there don't seem to be a lot of help online on how to interpret the results. Does ...
23 views

Statistical specification for a Regression with continuous finite range count like data

I am interested in explaining what kind of personal characteristics and work environment variables are associated with sickness absenteeism. My dependent variable is the total number of days a given ...
21 views

...
38 views

Is my data inappropriate for a zero-inflated regression model?

I am working with count data where I have an abundance of zeros for one of my categorical factors (Day). I have generated two models, p1 and m1, with zeroinfl() and ...
51 views

Zero-inflated model predicting only a small range of values. I need help

I built a ZI model and it is producing predicted values that are from a very small range when compared to the observed values. Plus it does not produce any zeros. See the fitted vs. observed graph ...
36 views

Variable importance when performing zero-inflated Poisson regression in R?

In short, I need to get the importance of the variables after a zero-inflated regression, with all my predictors being dichotomous factors. I tried something like this: ...
15 views

Yes/no GZLMM zero inflated

I have got a variable which I want to analyse using a GZLMM with binomial distribution as the variable is coded as yes/no(1/0). However, there are a lot of zeros and not many 1's.I was hoping to ...
25 views

What coefficients to include in logit component of zero-inflated and hurdle models?

I'm new to statistics so hoping for a ELI5 explanation! I need to use a hurdle (or zero-inflated) model to try and replicate someone elses methodology on a newer dataset for my undergraduate ...
106 views

My data has overdispersion but the Hurdle model estimated theta is 0. What am I doing wrong?

I am confused by the dispersion parameter from my model. My data fails the overdispersion test. It's mean is 28.7, the variance is 18655.27. N=2916 of which 32% are zeros. How can theta equal 0 in ...
28 views

Different significance found in zero-inflated negative binomial vs. binomial logistic regression

I'm having a hard time reconciling two seemingly contradictory findings: In a binomial logistic regression (where 0 is abstinent and 1 is relapsed), the 7 category nominal predictor showed ...
246 views

GLM Frequency and Severity Models. How Do I improve from here? (R code) [closed]

Background: I've been tasked with creating a rating model by Peril using GLMs. It's commercial lines property, so the data is pretty sparse. The carriers have been asking for Premiums by peril, so we'...
101 views

Zero-inflated vs not Zero-inflated models for count data

I am analyzing a small dataset (d) of urinary track infections in a group of residents of a long-term care institution over a period of 6 months. The total number of patients was 29. I had used ...
76 views

Handling quasi-perfect separation in a zero-inflated negative binomial regression in R

I want to run a zero-inflated negative binomial regression in R, but one of my variables exhibits quasi-complete separation and throws errors for both the negative binomial and logistic pieces. I've ...
82 views

Using gamm4 on zero-inflated count data with Tweedie or zero-inflated Poisson distributions

I'm working with a dataset with a large number of zero-counts on the response variable. This dataset consists of qualitatively coded interviews in a number of important categories, but many of the ...
124 views

GLMMs for count data with glmmTMB: random slopes specification, cross-level-interaction and strange results

folks, I recently found the great glmmTMB package which I hoped would help me with my models. My data are 60,000 facebook posts that are nested in 51 companies (i.e., the posts by these companies). ...
153 views

General linear mixed model in R which will fit quasi family [closed]

I am trying to run a GLMM with a quasibinomial family (my data is 0 inflated and I have a negative min x value), but am receiving this error message as quasi families cannot be used in glmer: ...
Suppose we have a dataset $X$ of features and a target binary prediction $y\in\{0,1\}$ for each datapoint. Each row of $X$ consists of counts (a bag of features). We can normalize each row of $X$ to ...