Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Weighted Mean00:57

Weighted Mean

6.4K
While taking the arithmetic, geometric, or harmonic mean of a sample data set, equal importance is assigned to all the data points. However, all the values may not always be equally important in some data sets. An intrinsic bias might make it more important to give more weightage to specific values over others.
For example, consider the number of goals scored in the matches of a tournament. While computing the average number of goals scored in the tournament, it may be more important to...
6.4K
Power01:08

Power

13.1K
The concept of work involves force and displacement; meanwhile, the work-energy theorem relates the net work done on a body to the difference in its kinetic energy, calculated between two points on its trajectory. While none of these quantities or relations involves time explicitly, we know that the time available to accomplish work is often just as important as the amount of work itself. For example, sprinters in a race may have achieved the same velocity at the finish, therefore,...
13.1K
Atomic Weight01:25

Atomic Weight

13.7K
Protons and neutrons have approximately the same mass, about 1.67 × 10-24 grams. Scientists arbitrarily define this amount of mass as one atomic mass unit (amu) or one Dalton. Electrons are much smaller in mass than protons, weighing only 9.11 × 10-28 grams, or about 1/1800 of an atomic mass unit. As a result, they do not contribute much to an element's overall atomic mass. This means that, when considering atomic mass, it is customary to ignore the mass of any electrons and...
13.7K
Mass and Weight01:19

Mass and Weight

15.3K
Mass and weight are often used interchangeably in everyday conversation. For example,  medical records often show our weight in kilograms, but never in the correct units of newtons. In physics, however, there is an important distinction. Weight is the pull of the Earth on an object. It depends on the distance from the center of the Earth. Weight dramatically varies if we leave the Earth's surface, unlike mass, which does not vary with location. On the Moon, for example, the...
15.3K
Apparent Weight01:09

Apparent Weight

9.8K
True weight is the measure of the gravitational force acting on an object. However, if the object accelerates, its measured weight is different from its true weight. Similar observations can be made when the object is submerged in water. An object's weight in water is its apparent weight, which is equal to the difference between its true weight and the buoyant forces.
Consider a person standing on a bathroom scale inside an elevator. If the scale is accurate at rest, its reading equals the...
9.8K
Instantaneous Power01:22

Instantaneous Power

923
Instantaneous power is important in electrical circuits, mainly when dealing with sinusoidal input. Instantaneous power, denoted as p(t), results from the multiplication of the instantaneous voltage (v(t)) across an element and the instantaneous current (i(t)) flowing through it. This relationship adheres to the passive sign convention and represents a fundamental principle in electrical engineering.
923

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Analyses of histological and transcriptome differences in the skin of short-hair and long-hair rabbits.

BMC genomics·2019
Same author

Magnetic Liquid Metals Manipulated in the Three-Dimensional Free Space.

ACS applied materials & interfaces·2019
Same author

First-line treatment of patients with advanced or metastatic squamous non-small cell lung cancer: systematic review and network meta-analysis.

Journal of thoracic disease·2019
Same author

Permeability of the porcine iris stroma.

Experimental eye research·2019
Same author

Lung Adenocarcinoma Harboring EGFR 19del/C797S/T790M Triple Mutations Responds to Brigatinib and Anti-EGFR Antibody Combination Therapy.

Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer·2019
Same author

Celecoxib With Neoadjuvant Chemotherapy for Breast Cancer Might Worsen Outcomes Differentially by COX-2 Expression and ER Status: Exploratory Analysis of the REMAGUS02 Trial.

Journal of clinical oncology : official journal of the American Society of Clinical Oncology·2019

Related Experiment Video

Updated: Feb 6, 2026

Visualizing Visual Adaptation
04:43

Visualizing Visual Adaptation

Published on: April 24, 2017

9.6K

A Powerful and Self-Adaptive Weighted Logrank Test.

Zhiguo Li1, Xiaofei Wang1

  • 1Department of Biostatistics & Bioinformatics, Duke University, Durham, North Carolina, USA.

Statistics in Medicine
|February 4, 2026
PubMed
Summary

A new weighted logrank test adaptively determines optimal weights for survival analysis. This approach enhances statistical power and maintains type I error control, outperforming existing methods in clinical trial simulations.

Keywords:
adaptive weightoptimal weightright censoringtype I error controlweighted logrank test

More Related Videos

Computerized Adaptive Testing System of Functional Assessment of Stroke
05:21

Computerized Adaptive Testing System of Functional Assessment of Stroke

Published on: January 7, 2019

6.3K
Use of a Hanging-weight System for Liver Ischemia in Mice
05:53

Use of a Hanging-weight System for Liver Ischemia in Mice

Published on: August 7, 2012

16.5K

Related Experiment Videos

Last Updated: Feb 6, 2026

Visualizing Visual Adaptation
04:43

Visualizing Visual Adaptation

Published on: April 24, 2017

9.6K
Computerized Adaptive Testing System of Functional Assessment of Stroke
05:21

Computerized Adaptive Testing System of Functional Assessment of Stroke

Published on: January 7, 2019

6.3K
Use of a Hanging-weight System for Liver Ischemia in Mice
05:53

Use of a Hanging-weight System for Liver Ischemia in Mice

Published on: August 7, 2012

16.5K

Area of Science:

  • Biostatistics
  • Survival Analysis
  • Clinical Trials

Background:

  • Weighted logrank tests (e.g., Harrington-Fleming, Tarone-Ware) use fixed weights to enhance power by emphasizing specific survival distribution differences.
  • While an optimal weight function exists theoretically, it cannot be directly applied due to type I error control issues and has an unachievable power upper bound.

Purpose of the Study:

  • To develop a novel weighted logrank test that self-adaptively determines an "optimal" weight function.
  • To improve statistical power in survival analysis while ensuring proper control of type I error rates.
  • To provide a robust and powerful method for comparing survival distributions in clinical research.

Main Methods:

  • Derived the theoretical upper bound for the power of weighted logrank tests with proper type I error control.
  • Proposed a new weighted logrank test utilizing a self-adaptive mechanism to determine the weight function.
  • Tuned a parameter within the proposed test to maintain type I error rates.

Main Results:

  • The proposed weighted logrank test demonstrated superior power compared to existing standard and weighted logrank tests.
  • The new test effectively maintained proper type I error rates across various scenarios.
  • Extensive simulation studies confirmed the test's high power and robustness.
  • The method was successfully illustrated using lung cancer clinical trial data.

Conclusions:

  • The proposed self-adaptive weighted logrank test offers a powerful and robust alternative for survival data analysis.
  • This method overcomes limitations of previous weighted logrank tests by balancing power and type I error control.
  • The adaptive approach provides a practical tool for enhancing the analysis of clinical trial data, particularly in oncology.