7 citations · 23 across the 22 of their papers we have counts for
22 papers
Bartholomew's trend test -- approximated by a multiple contrast test
Ludwig A. Hothorn
Bartholomew's trend test belongs to the broad class of isotonic regression models, specifically with a single qualitative factor, e.g. dose levels. Using the approximation of the A…
Consistent ANOVA-type tests for various effect sizes
Ludwig A. Hothorn
Analysis of variance (ANOVA) reveals some disadvantages, such as non-robustness against heteroscedastic or non-normal errors and using difference to overall mean as effect sizes on…
The Dunnett procedure with possibly heterogeneous variances
Ludwig A. Hothorn, Mario Hasler
Most comparisons of treatments or doses against a control are performed by the original Dunnett single step procedure \cite{Dunnett1955} providing both adjusted p-values and simult…
The Kruskal Wallis test can not be recommended
Ludwig A. Hothorn
Although the Kruskal-Wallis (KW) test is widely used, it should not be recommended: it is not robust to arbitrary alternatives, it is only a global test without confidence interval…
Seven recommendations for alternatives to the common analysis of variance (ANOVA) with application in the life sciences -- using R
Ludwig A. Hothorn
Standard ANOVA is among the most widely used tests in the life sciences and beyond. Several alternatives are proposed to provide simultaneous confidence intervals, ensure tight con…
Simultaneous confidence intervals for the interpretation of primary and secondary effects in factorial designs without a pre-test on interaction
Ludwig A. Hothorn
The analysis of low dimensional factorial designs with possible interactions is a relevant issue. Instead of the common pre-tests for interaction, a simultaneous inference procedur…
Evaluation of histological findings with severity grade, to analyze toxicology in-vivo studies
Ludwig A. Hothorn, Klaus Weber
In-vivo toxicological studies are characterized by multiple primary endpoints with quite different scales. Whereas guidelines and publications provide various statistical tests for…
Simultaneous inference of correlated marginal tests using intersection-union or union-intersection test principle
Ludwig A. Hothorn
Two main approaches in simultaneous inference are intersection-union tests and union-intersection tests. For intersection-union hypotheses, the classical IUT based on marginal p-va…
Closed testing procedures for treatment-versus-control comparisons and multiple correlated endpoint
Ludwig A. Hothorn, Siegfried Kropf
Preferably in two- or three-arm randomized clinical trials, a few (2,3) correlated multiple primary endpoints are considered. In addition to the closed testing principle based on d…
Simultaneous comparisons of treatments versus control (Dunnett-type tests) for location-scale alternatives
Ludwig A. Hothorn
Commonly, the comparisons of treatment groups versus a control is performed for location effects only where possible scale effects are considered as disturbing. Sometimes scale eff…
A statistical method for estimating the no-observed-adverse-event-level
Ludwig A. Hothorn
In toxicological risk assessment the benchmark dose (BMD) is recommended instead of the no-observed-adverse effect-level (NOAEL). Still a simple test procedure to estimate NOAEL is…
Closed test procedures for the comparison of dose groups against a negative control group or placebo
Ludwig A. Hothorn
Dose groups are compared with a control assuming an order restriction usually by the Williams trend test. Here, as an alternative, two variants of the closed testing procedure are…
Comparisons of multiple treatment groups with a negative control or placebo group: Dunnett test vs. closed test procedur
Ludwig A. Hothorn
Several treatments are usually compared with a control using the Dunnett test. As an alternative, three variants of the closed testing approach are considered, one with ANOVA-F-tes…
Comparisons of proportions in k dose groups against a negative control assuming order restriction: Williams-type test vs. closed test procedures
Ludwig A. Hothorn
The comparison of proportions is considered in the asymptotic generalized linear model with the odds ratio as effect size. When several doses are compared with a control assuming a…
Statistical evaluation of in-vivo bioassays in regulatory toxicology considering males and females
Ludwig A. Hothorn
The separate evaluation for males and females is the recent standard in in-vivo toxicology for dose or treatment effects using Dunnett tests. The alternative pre-test for sex-by-tr…
Similarity of multiple dose-response curves in interlaboratory studies in regulatory toxicology
Ludwig A. Hothorn, Dimitrios Spiliotopoulos
To claim similarity of multiple dose-response curves in interlaboratory studies in regulatory toxicology is a relevant issue during the assay validation process. Here we demonstrat…
A versatile trend test for the evaluation of tumor incidences in long-term carcinogenicity bioassays
Ludwig A. Hothorn, Atiar M. Rahman, Frank Schaarschmidt
For the evaluation of carcinogenicity bioassays a new trend test is proposed which is based on a maximum of arithmetic, ordinal, and logarithmic regression scores as well as the Wi…
Model-based simultaneous inference for multiple subgroups and multiple endpoints
Charlotte Vogel, Frank Schaarschmidt, Christian Ritz +2
Various methodological options exist on evaluating differences in both subgroups and the overall population. Most desirable is the simultaneous study of multiple endpoints in sever…
Claiming trend in toxicological and pharmacological dose-response studies: an overview on statistical methods and related R-Software
Ludwig A. Hothorn
There are very different statistical methods for demonstrating a trend in pharmacological experiments. Here, the focus is on sparse models with only one parameter to be estimated a…
A Tukey type trend test for repeated carcinogenicity bioassays, motivated by multiple glyphosate studies
Ludwig A. Hothorn, Frank Schaarschmidt
In the last two decades, significant methodological progress to the simultaneous inference of simple and complex randomized designs, particularly proportions as endpoints, occurred…
A modified Armitage test for more than a linear trend on proportions
Ludwig A. Hothorn, Frank Schaarschmidt
The Armitage test for linear trend in proportions can be modified using the multiple marginal model approach for three regression models with arithmetic, ordinal and logarithmic do…
Robust multiple comparisons against a control group with application in toxicology
Ludwig A. Hothorn, Felix M. Kluxen
The Dunnett procedure compares several treatment or dose groups with a control group, while controlling the familywise error rate. When deviations from the normal distribution and…