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

Sample Size Calculation01:19

Sample Size Calculation

6.7K
Knowledge of the sample size is the first requirement to conduct random sampling or an experiment. The sample size is the total number of units, observations, or groups (in some cases) used to get the data to estimate a population parameter. As the name suggests, the sample size is that of the sample drawn from the population and differs from the population size.
The sample size for the given experiment or sampling effort is fundamental to any study design. Sample size decides the number of...
6.7K
Clinical Trials01:16

Clinical Trials

10.5K
Clinical trials are prospective experimental studies conducted on humans to determine the safety and efficacy of treatments, drugs, diet methods, and medical devices. Using statistics in clinical trials enables researchers to derive reasonable and accurate conclusions from the collected data, allowing them to make wise decisions in uncertain situations. In medical research, statistical methods are crucial for preventing errors and bias.
There are four phases in a clinical trial. A phase one...
10.5K
Clinical Trials: Overview01:11

Clinical Trials: Overview

4.9K
Clinical development focuses on how the drug will interact with the human body and encompasses four key phases of clinical trials, each serving a specific purpose in assessing the safety and effectiveness of new drugs. These phases overlap and build upon one another. Phase I involves a small group of healthy volunteers (typically 20-80 individuals) or, in cases where significant toxicity is expected, patients with the targeted disease, such as cancer or AIDS. The volunteers are tested for...
4.9K
Statistical Software for Data Analysis and Clinical Trials01:12

Statistical Software for Data Analysis and Clinical Trials

1.5K
Statistical software is pivotal in data analysis and clinical trials by providing tools to analyze data, draw conclusions, and make predictions. These software packages range from simple data management applications to complex analytical platforms, supporting various statistical tests, models, and simulation techniques. Their significance lies in their ability to handle vast amounts of data with precision and efficiency, enabling researchers to validate hypotheses, identify trends, and make...
1.5K
One-Way ANOVA: Unequal Sample Sizes01:15

One-Way ANOVA: Unequal Sample Sizes

6.7K
One-way ANOVA can be performed on three or more samples of unequal sizes. However, calculations get complicated when sample sizes are not always the same. So, while performing ANOVA with unequal samples size, the following equation is used:
6.7K
One-Way ANOVA: Equal Sample Sizes01:15

One-Way ANOVA: Equal Sample Sizes

4.1K
One-Way ANOVA can be performed on three or more samples with equal or unequal sample sizes. When one-way ANOVA is performed on two datasets with samples of equal sizes, it can be easily observed that the computed F statistic is highly sensitive to the sample mean.
Different sample means can result in different values for the variance estimate: variance between samples. This is because the variance between samples is calculated as the product of the sample size and the variance between the...
4.1K

You might also read

Related Articles

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

Sort by
Same author

Availability of mechanical circulatory support (MCS) and hospital survival in ST-segment elevation myocardial infarction related cardiogenic shock (STEMI-CS).

European heart journal. Acute cardiovascular care·2026
Same author

Effects of fasudil on disease spreading in ALS - A MUNIX-based post-hoc analysis of the ROCK-ALS trial.

Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics·2026
Same author

Stratification of children with myocarditis using radiomics signatures in LGE cardiovascular MRI.

Computer methods and programs in biomedicine·2026
Same author

Does an app make patients happy? Impact of a novel medical history app on patient satisfaction in urgent care consultations in Germany: cluster-randomized interventional trial 'DASI'.

BMC health services research·2026
Same author

Stem-Cell-Derived Biologic Ventricular Assist Tissue in Heart Failure.

The New England journal of medicine·2026
Same author

Baroreflex Activation Therapy In Heart Failure-the Barostim-Enabled Neurohormonal Intervention for Improving Treatment of Heart Failure (BENEFIT-HF) Trial Rationale and Design.

Journal of cardiac failure·2026
Same journal

Sparse multi-way DMDC for longitudinal classification in high dimension low sample size data.

BMC medical research methodology·2026
Same journal

Tree-based exploratory identification of predictive biomarkers in non-randomized data.

BMC medical research methodology·2026
Same journal

Comparative evaluation of interrupted time series analytical methods for healthcare quality improvement research: a Monte Carlo simulation study.

BMC medical research methodology·2026
Same journal

Methodological advances in claims-based dementia algorithms: integrating medication and clinical data for medicare populations.

BMC medical research methodology·2026
Same journal

An interpretable XGboost algorithm for predicting 30-day mortality in acute pancreatitis using routine biomarkers.

BMC medical research methodology·2026
Same journal

Increasing power and robustness in screening trials by testing stored specimens in the control arm.

BMC medical research methodology·2026
See all related articles

Related Experiment Video

Updated: Feb 1, 2026

In Silico Clinical Trials for Cardiovascular Disease
09:09

In Silico Clinical Trials for Cardiovascular Disease

Published on: May 27, 2022

2.3K

Sample size calculation in multi-centre clinical trials.

Markus Harden1, Tim Friede2

  • 1Department of Medical Statistics, University Medical Centre Göttingen, Humboldtallee 32, Göttingen, 37073, Germany. markus.harden@med.uni-goettingen.de.

BMC Medical Research Methodology
|December 1, 2018
PubMed
Summary
This summary is machine-generated.

A new sample size formula for multi-centre trials accounts for unbalanced treatment allocation and centre heterogeneity. This method improves power compared to conventional approaches, guiding better clinical trial planning.

Keywords:
Block randomisationLinear mixed modelRandom effects

More Related Videos

Characterizing Exon Skipping Efficiency in DMD Patient Samples in Clinical Trials of Antisense Oligonucleotides
05:16

Characterizing Exon Skipping Efficiency in DMD Patient Samples in Clinical Trials of Antisense Oligonucleotides

Published on: May 7, 2020

7.3K
Enumeration of Major Peripheral Blood Leukocyte Populations for Multicenter Clinical Trials Using a Whole Blood Phenotyping Assay
14:45

Enumeration of Major Peripheral Blood Leukocyte Populations for Multicenter Clinical Trials Using a Whole Blood Phenotyping Assay

Published on: September 16, 2012

15.5K

Related Experiment Videos

Last Updated: Feb 1, 2026

In Silico Clinical Trials for Cardiovascular Disease
09:09

In Silico Clinical Trials for Cardiovascular Disease

Published on: May 27, 2022

2.3K
Characterizing Exon Skipping Efficiency in DMD Patient Samples in Clinical Trials of Antisense Oligonucleotides
05:16

Characterizing Exon Skipping Efficiency in DMD Patient Samples in Clinical Trials of Antisense Oligonucleotides

Published on: May 7, 2020

7.3K
Enumeration of Major Peripheral Blood Leukocyte Populations for Multicenter Clinical Trials Using a Whole Blood Phenotyping Assay
14:45

Enumeration of Major Peripheral Blood Leukocyte Populations for Multicenter Clinical Trials Using a Whole Blood Phenotyping Assay

Published on: September 16, 2012

15.5K

Area of Science:

  • Clinical Trials Methodology
  • Biostatistics
  • Evidence-Based Medicine

Background:

  • Multi-centre randomized controlled trials are crucial for evidence-based medicine, offering accelerated recruitment and generalizability.
  • Mixed models can address data clustering in multi-centre trials, but existing sample size methods often assume balanced treatment allocations, which is rare in practice with block randomization.

Purpose of the Study:

  • To propose a sample size determination procedure for multi-centre trials with continuous outcomes, accommodating random effects for centre differences and unequal sample sizes.
  • To allow for block randomization with fixed block lengths at each study site for subject allocation.

Main Methods:

  • Developed a sample size formula and calculated lower/upper boundaries for multi-centre trials.
  • Utilized simulations to evaluate the power and operating characteristics of the proposed sample size approach.
  • Applied the procedure to an example in disease management systems.

Main Results:

  • The new sample size formula demonstrates superiority over conventional methods that ignore the multi-centre structure.
  • Demonstrated the impact of block length and centre heterogeneity on required sample size.
  • Showed that large blocks necessitate larger sample sizes when centre heterogeneity is present.

Conclusions:

  • Unbalanced treatment allocation significantly reduces statistical power in the presence of centre heterogeneity if not considered during planning.
  • A balance must be struck between the risk of treatment group imbalance (large blocks) and unblinding (small blocks) when planning trials with few patients per centre.
  • The proposed sample size determination procedure is recommended for the planning stages of multi-centre trials.