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Related Concept Videos

Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches01:23

Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches

Biopharmaceutical studies constitute a vital field aiming to enhance drug delivery methods and refine therapeutic approaches, drawing upon diverse interdisciplinary knowledge. In research methodologies, the choice between controlled and non-controlled studies significantly influences the study's reliability and accuracy.
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast, controlled...
Blinding01:11

Blinding

Blinding is a commonly used method of not telling participants which treatment a subject is receiving. Blinding is a critical part of a randomized control trial or RCT. It reduces the bias that affects the results. In an RCT, blinding is used in the form of a placebo. A placebo effect occurs when untreated subjects falsely believe they have received the treatment and report improved symptoms. A placebo or a dummy treatment is administered to subjects to negate the bias caused by such an effect.
Sample Size Calculation01:19

Sample Size Calculation

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...
Blind Procedures02:07

Blind Procedures

Ideally, the people who observe and record the children’s behavior are unaware of who was assigned to the experimental or control group, in order to control for experimenter bias. Experimenter bias refers to the possibility that a researcher’s expectations might skew the results of the study. Remember, conducting an experiment requires a lot of planning, and the people involved in the research project have a vested interest in supporting their hypotheses. If the observers knew which child was...
Statistical Software for Data Analysis and Clinical Trials01:12

Statistical Software for Data Analysis and Clinical Trials

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...
Clinical Trials01:16

Clinical Trials

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...

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Related Experiment Video

Updated: Jun 18, 2026

A Clinical Trial Assessing the Safety, Efficacy, and Delivery of Olive-Oil-Based Three-Chamber Bags for Parenteral Nutrition
04:53

A Clinical Trial Assessing the Safety, Efficacy, and Delivery of Olive-Oil-Based Three-Chamber Bags for Parenteral Nutrition

Published on: September 20, 2019

Blinded sample size recalculation for clinical trials with normal data and baseline adjusted analysis.

Tim Friede1, Meinhard Kieser

  • 1Warwick Medical School, The University of Warwick, Coventry, UK.

Pharmaceutical Statistics
|November 28, 2009
PubMed
Summary

This study introduces an internal pilot study design for clinical trials, allowing for sample size recalculation. This approach maintains accurate Type I error rates and statistical power, making it practical for researchers.

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Published on: January 8, 2020

Area of Science:

  • Biostatistics
  • Clinical Trial Design

Background:

  • Baseline adjusted analyses are standard in clinical practice and endorsed by regulatory bodies.
  • Accurate sample size calculations require nuisance parameter estimates, often unavailable during initial planning.

Purpose of the Study:

  • To investigate the characteristics of an internal pilot study design for sample size recalculation.
  • To assess the accuracy of sample size formulae and the performance of recalculation procedures in analysis of covariance models.

Main Methods:

  • Utilized an internal pilot study design with analysis of covariance and a random covariate.
  • Assessed four approximate sample size formulae for fixed sample size designs.
  • Examined the Type I error rate and power of the recalculation procedure via simulation studies.

Main Results:

  • The internal pilot study design demonstrated favorable properties regarding Type I error rate and statistical power.
  • Simulation studies confirmed the accuracy and effectiveness of the sample size recalculation method.

Conclusions:

  • The proposed internal pilot study design with sample size recalculation is a simple and effective approach.
  • This method is attractive for practical application in clinical trials due to its favorable statistical properties.