ArticleStatistical methods in medical research2016
Estimating the sample size for a pilot randomised trial to minimise the overall trial sample size for the external pilot and main trial for a continuous outcome variable.
49 registry-linked trialsAbstract read
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Article in Statistical methods in medical research, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to 49 registered trials, which are not on this map. Cited by 1,052 papers.
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1,052citing papers in PubMed
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What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
ORAL ANTIDIABETICS EFFECT ON VISCERAL FAT MEASURED BY BIOIMPEDANCE IN TYPE 2 DIABETES PATIENTS. Pilot Study.
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Who cites it
1,052 citing papers in PubMed.
- Acceptability and Feasibility of an Islamic Faith-Based Smoking Cessation Intervention Delivered via WhatsApp for Muslim Smokers in Saudi Arabia: Pilot Randomized Controlled Trial.JMIR formative research · 2026Trial
- High-Flow Nasal Oxygen in Early Home Pulmonary Rehabilitation for Exertional Hypoxaemia: A Pilot Randomised Feasibility Trial.Respirology (Carlton, Vic.) · 2026Trial
- Feasibility of a Virtual Mindfulness-Based Stress Reduction Intervention for Individuals With Chronic Pain: Pilot Randomized Controlled Trial.JMIR formative research · 2026Trial
- Effects of a Group-Based Cognitive Behavioral Therapy for Sleep in Nursing Students: Pilot Randomized Controlled Trial.JMIR human factors · 2026Trial
- Trial
- Comparison of Continuous and Gait-synchronized Transcutaneous Electrical Nerve Stimulation During Gait Training in Chronic Stroke: A Pilot Randomized Trial.Revista de neurologia · 2026Trial
- REstrictive versus StandarD FlUid Management in Mechanically Ventilated ChildrEn Admitted to PICU: a pilot randomized controlled trial (REDUCE-1).Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies · 2026Trial
- A Co-Designed Post-ICU Follow-Up Pathway Is Feasible and May Be Associated With Improved Psychosocial Recovery for Patients and Their Caregivers: Outcomes From the IMPACT-ICU Single-Center Randomized Controlled Trial.Critical care explorations · 2026Trial
- Effects of a Psycho-Behavioural Intervention on Cancer-Related Fatigue Among Patients With Colorectal Cancer: A Pilot Randomised Controlled Trial.Psycho-oncology · 2026Trial
- Efficacy and Adherence to a Supervised Aerobic Exercise Training Intervention in Night-Shift Hospital Nurses: A Randomized Controlled Trial.FASEB journal : official publication of the Federation of American Societies for Experimental Biology · 2026Trial
- Assessment of classification accuracy in endodontics by dental students: a comparative study of holographic imaging and conventional radiography.BMC medical education · 2026Trial
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- Adjunctive ibuprofen in pre-extensively drug-resistant and extensively drug-resistant tuberculosis: a phase IIA open-label pilot clinical trial.Nature communications · 2026Trial
- AutInsight: A Pilot Randomised Controlled Trial (RCT) of a Consumer-Informed Parent Support Program for Parents of Autistic Children.Journal of autism and developmental disorders · 2026Trial
- Application of a cancer pain belief modification program for patients with oral cancer in China: a mixed methods study.Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer · 2026Trial
- Does Combined Intravenous and Topical Tranexamic Acid Offer Additional Benefit Compared With Intravenous or Topical Alone in Open Elbow Arthrolysis-A Pilot Randomized Controlled Trial.Orthopaedic surgery · 2026Trial
- Cognitive muscular therapy™ for knee osteoarthritis: A feasibility randomised controlled trial.Osteoarthritis and cartilage open · 2026Trial
- Pilot Randomized Controlled Trial of Krill Oil Supplementation for Chronic Musculoskeletal Pain in Older Adults.The Journal of nutrition · 2026Trial
- Evaluation of a transdiagnostic mental health intervention in German primary care: a parallel-group, two-arm, cluster randomised controlled pilot study.BMC primary care · 2026Trial
- Exercise-Based Rehabilitation in Severe COVID-19 Survivors with Long COVID: A Randomized Controlled Pilot Study.Medical sciences (Basel, Switzerland) · 2026Trial
992 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors.
Amy L WhiteheadMedical Statistics Group, Design, Trials and Statistics Group, School of Health and Related Research, University of Sheffield, Sheffield, UK a.whitehead@sheffield.ac.uk.
Steven A JuliousMedical Statistics Group, Design, Trials and Statistics Group, School of Health and Related Research, University of Sheffield, Sheffield, UK.
Cindy L CooperClinical Trials Research Unit, Design, Trials and Statistics Group, School of Health and Related Research, University of Sheffield, Sheffield, UK.
Michael J CampbellMedical Statistics Group, Design, Trials and Statistics Group, School of Health and Related Research, University of Sheffield, Sheffield, UK.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Sample size justification is an important consideration when planning a clinical trial, not only for the main trial but also for any preliminary pilot trial. When the outcome is a continuous variable, the sample size calculation requires an accurate estimate of the standard deviation of the outcome measure. A pilot trial can be used to get an estimate of the standard deviation, which could then be used to anticipate what may be observed in the main trial. However, an important consideration is that pilot trials often estimate the standard deviation parameter imprecisely. This paper looks at how we can choose an external pilot trial sample size in order to minimise the sample size of the overall clinical trial programme, that is, the pilot and the main trial together. We produce a method of calculating the optimal solution to the required pilot trial sample size when the standardised effect size for the main trial is known. However, as it may not be possible to know the standardised effect size to be used prior to the pilot trial, approximate rules are also presented. For a main trial designed with 90% power and two-sided 5% significance, we recommend pilot trial sample sizes per treatment arm of 75, 25, 15 and 10 for standardised effect sizes that are extra small (≤0.1), small (0.2), medium (0.5) or large (0.8), respectively.
Indexed as
Pilot ProjectsHumansOutcome Assessment, Health CareRandomized Controlled Trials as TopicSample Sizecontinuous outcomePilot trialpowerRCTsample size
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Registered trials
NCT05032001ClinicalTrials.gov
NCT03159962ClinicalTrials.gov
NCT03188978ClinicalTrials.gov
NCT03514316ClinicalTrials.gov
NCT03821896ClinicalTrials.gov
NCT03825770ClinicalTrials.gov
and 43 more above
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.