How to conduct a clinical trial

Reviewed and revised 26 August 2015


  • This page provides a broad overview of the complicated process of conducting a clinical trial
  • Conducting a clinical trial can be conceptualised as having 14 key steps


(1) Research question

  • is it worth while?
  • could it help improve patient outcome?

(2) Define hypothesis

  • take an opinion on what the answer to the question is.

(3) Literature review

  • make sure no one has already conclusively answered the question
  • make sure it’ll benefit patients

(4) Involve statistician, and discuss:

  • type of study
  • calculate sample size (alpha and beta values, power, effect size , variance of population)
  • how to reduce bias:
    • -> blinding (single, double or triple)
    • -> crossover
    • -> randomization
    • -> controls

(5) Develop inclusion & exclusion criteria

  • stick to them when carrying out study!

(6) Calculate sample size needed

  • beta value and power (small sample size is the commonest cause of a false negative result)
  • alpha value (e.g. p < 0.05; limits false positive results)
  • variance of population
  • effect size
  • statistical test

(7) Develop methodology

  • treatment
  • doses
  • side effects
  • placebo
  • how to collect information

(8) Gain ethical approval

  • consider professional virtue of medical loyalty
  • autonomy, non-maleficence, beneficence & distributive justice.

Some issues include

  • use of placebos when efficacious therapy available
  • whether every research participant needs to sign a written consent
  • whether informed consent is necessary (ICU patients)
  • accepting drug company gifts
  • misleading information from the drug reps.

(9) Perform pilot study

  • modify protocol based on pilot study

(10) Carry out study

  • patient information & informed consent important
  • collect data
  • measure outcomes
  • monitor safety

(11) Analysis

  • using appropriate statistical methods

(12) Compare to null hypothesis

  • proven or disproven
  • statistically significant difference or not

(13) Consider errors

  • sources of bias
  • patients lost to follow up
  • adverse effects
  • surprising benefits

(14) Submit for publication

  • survive the peer review process and hope that the article is accepted!
  • educate others of the findings so it can be implemented into clinical practice (knowledge translation)

References and Links


CCC 700 6

Critical Care


Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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