Education researchers often study count variables, such as times a student reached a goal, discipline referrals, and absences. Most researchers that study these variables use typical regression methods (i.e., ordinary least-squares) either with or without transforming the count variables. In either case, using typical regression for count data can produce parameter estimates that are biased, th...

Count data are increasingly ubiquitous in genetic association studies, where it is possible to observe excess zero counts as compared to what is expected based on standard assumptions. For instance, in rheumatology, data are usually collected in multiple joints within a person or multiple sub-regions of a joint, and it is not uncommon that the phenotypes contain enormous number of zeroes due to...

In a Poisson regression model, where observations are either clustered or represented by repeated measurements of counts, the number of observed zero counts is sometimes greater than the expected frequency by the Poisson distribution and the non-zero part of count data may be overdispersed. The zero-inflated negative binomial (ZINB) mixed regression model is suggested to analyze such data. Prev...

background: occupational injury is related to personal characteristics. this phenomenon is a controversial issue. this paper presents the relationships of certain occupational and individual characteristics with frequency of occupational injuries. methods : a standardized injury questionnaire was completed for 199 employees in a big iranian industrial company (mapna group) by the researcher in ...

GENERALIZED ESTIMATING EQUATION BASED ZERO-INFLATED MODEL WITH APPLICATION TO EXAMINING THE RELATIONSHIP BETWEEN DENTAL CARIES AND FLUORIDE EXPOSURES Sheng Xu April 16, 2013 In the study of dental caries, the number of caries is frequently characterized by over-dispersion and excessive zeros. In addition, the numbers of caries from the same subject are correlated. Zero-Inflated (ZI) regression ...

Text data modeling has been usually considered with Bernoulli or multinomial event models. Poisson distribution is considered inefficient for text information retrieval. In this work, we propose to incorporate the Zero Inflated Poisson model in the Generative Topographic Mapping algorithm. The modified algorithm is presented as a text document cluster extraction and visualization tool. Experime...

Abstract The risk of maternal death in developing countries is projected to be one 61, while for developed it estimated 2800. Antenatal care a protective obstetric health system aimed at improving the outcome pregnant fetus by routine pregnancy monitoring. One most important functions antenatal offer information and services that can significantly improve women their infants. 6450 from Ethiopia...

This paper describes a compound Poisson-based random effects structure for modeling zero-inflated data. Data with large proportion of zeros are found in many fields of applied statistics, for example in ecology when trying to model and predict species counts (discrete data) or abundance distributions (continuous data). Standard methods for modeling such data include mixture and two-part conditi...

Motivated by a study of molecular differences among breast cancer patients, we develop a Bayesian latent factor zero-inflated Poisson (LZIP) model for the analysis of correlated zero-inflated counts. The responses are modeled as independent zero-inflated Poisson distributions conditional on a set of subject-specific latent factors. For each outcome, we express the LZIP model as a function of tw...

This paper presents an empirical inquiry into the applicability of zero-altered counting processes to roadway section accident frequencies. The intent of such a counting process is to distinguish sections of roadway that are truly safe (near zero-accident likelihood) from those that are unsafe but happen to have zero accidents observed during the period of observation (e.g. one year). Tradition...