The Influence of Design Characteristics on Statistical Inference in Nonlinear Estimation: A Simulation Study Based on Survival Data and Hazard Modeling

2000 ◽  
Vol 5 (3) ◽  
pp. 323 ◽  
Author(s):  
J. S. Andersen ◽  
J. J. M. Bedaux ◽  
S. A. L. M. Kooijman ◽  
H. Holst
Keyword(s):  
Statistical Inference ◽  
Simulation Study ◽  
Survival Data ◽  
Nonlinear Estimation ◽  
Hazard Modeling ◽  
Design Characteristics

Mutans Streptococci and Dental Caries: A New Statistical Modeling Approach

2018 ◽  
Vol 52 (3) ◽  
pp. 246-252 ◽  
Author(s):  
Tariq S. Ghazal ◽  
Steven M. Levy ◽  
Noel K. Childers ◽  
Knute D. Carter ◽  
Daniel J. Caplan ◽  
...  
Keyword(s):  
Dental Caries ◽  
Low Socioeconomic Status ◽  
Survival Data ◽  
Mutans Streptococci ◽  
Time Dependent ◽  
Caries Experience ◽  
Acquisition Time ◽  
Hazard Modeling ◽  
Initial Caries

Survival analyses have been used to overcome some of the limitations encountered with other statistical analyses. Although extended Cox hazard modeling with time-dependent variables has been utilized in several medical studies, it has never been utilized in assessing the complex relationship between mutans streptococci (MS) acquisition (time-dependent covariate) and time to having dental caries (outcome). This study involved secondary analyses of data from a prospective study conducted at the University of Alabama at Birmingham. Low socioeconomic status, African-American preschool children from Perry County, AL, USA (n = 95) had dental examinations at age 1 year and annually thereafter until age 6 years by three calibrated dentists. Salivary MS tests were done at ages 1, 1.5, 2, 2.5, 3, and 4 years. The patterns of and relationship between initial MS detection (time-dependent covariate) and dental caries experience occurrence were assessed, using extended Cox hazard modeling. The median time without MS acquisition (50% of the children not having positive MS test) was 2 years. Approximately 79% of the children had positive salivary MS tests by the age of 4 years. The median caries experience survival (50% of the children not having dental caries) was 4 years. During the follow-up period, 65 of the children (68.4%) had their initial primary caries experience. Results of the extended Cox hazard modeling showed a significant overall/global relationship between initial caries experience event at any given time during the follow-up period and having a positive salivary MS test at any time during the follow-up period (hazard ratio = 2.25, 95% CI 1.06-4.75). In conclusion, the extended Cox modeling was used for the first time and its results showed a significant global/overall relationship between MS acquisition and dental caries. Further research using causal mediation analysis with survival data is necessary, where the mediator “presence of MS” is treated as a time-dependent variable.

scholarly journals Overlap coefficients based on Kullback-Leibler divergence: Exponential populations case

2017 ◽  
Vol 6 (4) ◽  
pp. 135
Author(s):  
Hamza Dhaker ◽  
Papa Ngom ◽  
Malick Mbodj
Keyword(s):  
Statistical Inference ◽  
Mean Square Error ◽  
Confidence Intervals ◽  
Taylor Series ◽  
Simulation Study ◽  
Invariance Property ◽  
Mean Square ◽  
Taylor Series Approximation ◽  
Leibler Divergence ◽  
Exponential Populations

This article is devoted to the study of overlap measures of densities of two exponential populations. Various Overlapping Coefficients, namely: Matusita’s measure ρ, Morisita’s measure λ and Weitzman’s measure ∆. A new overlap measure Λ based on Kullback-Leibler measure is proposed. The invariance property and a method of statistical inference of these coefficients also are presented. Taylor series approximation are used to construct confidence intervals for the overlap measures. The bias and mean square error properties of the estimators are studied through a simulation study.

Modeling exposures with a spike at zero: simulation study and practical application to survival data

2019 ◽  
Vol 3 (1) ◽  
pp. 23-37 ◽  
Author(s):  
Eva Lorenz ◽  
Carolin Jenkner ◽  
Willi Sauerbrei ◽  
Heiko Becher
Keyword(s):  
Simulation Study ◽  
Survival Data ◽  
Practical Application

scholarly journals method to streamline p-hacking

2021 ◽  
Vol 5 ◽  
Author(s):  
Ian Hussey
Keyword(s):  
Statistical Inference ◽  
Simulation Study ◽  
Research Funding ◽  
Innovative Approach ◽  
Random Numbers ◽  
Psychological Science ◽  
Widespread Adoption ◽  
Analytic Strategy

The analytic strategy of p-hacking has rapidly accelerated the achievement of psychological scientists’ goals (e.g., publications & tenure), but has suffered a number of setbacks in recent years. In order to remediate this, this article presents a statistical inference measure that can greatly accelerate and streamline the p-hacking process: generating random numbers that are < .05. I refer to this approach as pointless. Results of a simulation study are presented and an R script is provided for others to use. In the absence of systemic changes to modal p-hacking practices within psychological science (e.g., worrying trends such as preregistration and replication), I argue that vast amounts of time and research funding could be saved through the widespread adoption of this innovative approach.

scholarly journals A method to streamline p-hacking

2018 ◽  
Author(s):  
Ian Hussey
Keyword(s):  
Statistical Inference ◽  
Simulation Study ◽  
Research Funding ◽  
Innovative Approach ◽  
Random Numbers ◽  
Inference Method ◽  
Psychological Science ◽  
Widespread Adoption ◽  
Analytic Strategy

The analytic strategy of p-hacking has rapidly accelerated the achievement of psychological scientists’ goals (e.g., publications &amp; tenure), but has suffered a number of setbacks in recent years. In order to remediate this, this article presents a statistical inference method that can greatly accelerate and streamline the p-hacking process: generating random numbers that are &lt; .05. I refer to this approach as pointless. Results of a simulation study are presented and an R script is provided for others to use. In the absence of systemic changes to modal p-hacking practices within psychological science (e.g., worrying trends such as preregistration and replication), I argue that vast amounts of time and research funding could be saved through the widespread adoption of this innovative approach.

SHARP BOUNDS ON THE DISTRIBUTION OF TREATMENT EFFECTS AND THEIR STATISTICAL INFERENCE

2009 ◽  
Vol 26 (3) ◽  
pp. 931-951 ◽  
Author(s):  
Yanqin Fan ◽  
Sang Soo Park
Keyword(s):  
Sample Size ◽  
Statistical Inference ◽  
Confidence Intervals ◽  
Simulation Study ◽  
Treatment Effect ◽  
Treatment Effects ◽  
Asymptotic Distributions ◽  
Finite Sample ◽  
Sharp Bounds ◽  
Nonparametric Estimators

In this paper, we propose nonparametric estimators of sharp bounds on the distribution of treatment effects of a binary treatment and establish their asymptotic distributions. We note the possible failure of the standard bootstrap with the same sample size and apply the fewer-than-nbootstrap to making inferences on these bounds. The finite sample performances of the confidence intervals for the bounds based on normal critical values, the standard bootstrap, and the fewer-than-nbootstrap are investigated via a simulation study. Finally we establish sharp bounds on the treatment effect distribution when covariates are available.

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