What do medical statisticians and statistical programmers do?

Every new medicine that is invented must be thoroughly tested to prove that it is not only an effective treatment for a health problem, but that it is safe for patients and does not have any side effects that are too severe.

We do this by conducting clinical trials where patients are administered the experimental new treatment and are compared to a control group of patients administered a placebo or an existing treatment.


Before we go ahead and give patients treatments, we need to make sure that we have robustly designed our trial to give us the best chance of being able to demonstrate that the experimental new treatment is superior to the comparator control treatment.

Designing and conducting a clinical trial requires expertise from a wide range of professions, so statisticians and programmers get to enjoy working in cross-functional teams comprising medics, study managers, data managers, regulatory experts, and many more.

Their skills in maths and statistics allow them to make very valuable contributions to the clinical trial. Explore below just some of the activities they do in their day to day jobs.

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Medical Statisticians

The statistician has some very important jobs to do when designing a clinical trial. To start with, they must calculate how many patients are needed for the trial. We call this the sample size.

Calculate sample size

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If we treat too many patients then we risk exposing an unnecessary number of patients to an inferior treatment.

If we treat too few, then we risk not having enough evidence to prove that the new treatment is superior.

This is a critical calculation on which the success of the trial and many millions of pounds lie.

Randomise patients to treatment

It is the statistician’s job to allocate patients to the new treatment or to the placebo or control treatment. Treatments must be allocated at random so that the two groups are similar in every way except for the treatment they are given.

You can do a simple randomisation by tossing a coin and assigning all those who get a head to the control group and all those who get a tail to the new treatment group.

Choose appropriate analysis methods

Statisticians have a crucial job to make sure that data collected during the clinical trial is analysed using appropriate methods and is interpreted correctly.

They carry out statistical tests to weigh the evidence held in the data and determine whether the new drug is beneficial for patients.


Key skills

As well as their statistical qualifications, statisticians need to have good communication skills. They must interpret the results of statistical analyses and explain to non-statisticians, such as the medical team, what the results mean in layman’s terms.

Statisticians are often called upon to give input to decision-making. Their logical thinking and understanding of the whole clinical trial from data collection to analysis results is very valuable.

Statistical programmers

Statisticians and programmers work very closely together. In fact, in some companies these are not two separate jobs. Both need to be proficient in programming languages such as R and SAS.

Create datasets

The programmer makes sure that the data is ready to be analysed. This can include calculating new 
measurements, called endpoints, from the data already collected. For example, if we know the date on which a patient fully recovered, then we can calculate time to recovery (number of days from the start of the trial to the date of recovery).

Summarise Data

Programmers are experts in turning datasets into summary tables and graphs. The statistician and programmer collaborate to decide how the tables and graphs should look and what they should contain, and then the programmer makes these a reality.


Key skills

Programmers need to be skilled in paying attention to detail and they must carefully document their work so that analysis results are traceable from the raw data. Programmers must also be very organised and able to meet deadlines.

Clinical Trial Quick Facts

  • Usually the first people to try out a new medicine are healthy volunteers. Healthy volunteers are used to find the maximum dose the body can tolerate, then this is used in trials on patients.
  • In a ‘gold standard’ clinical trial neither the patient nor the doctor knows whether the drug being administered is the new experimental one or the control treatment. This is called double blinding.
  • Clinical trials tend to be global, enrolling patients from many countries around the world.
  • It costs over $2.5 billion in research and development costs to bring a drug to market to be prescribed to patients.

Check out the Next Steps page to find out how you can study and train to be a medical statistician or statistical programmer.

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EventsFuture Events

  • PSI Toxicology SIG Workshop 2019 - Dates: 02 – 03 Apr, 2019

    This 1.5-day workshop will involve approximately 20 statisticians, focusing on discussions around “best practice” in the statistical analysis of various data types.​
  • PSI Journal Club: Missing Data - Dates: 24 – 24 Jan, 2019

    Our next journal club, held jointly with the DIA, features two papers on the topic of Statistical Considerations for Innovative Designs in Clinical Trials. Please join us to hear Jason Yuan and Xiangmin Zhang present their recent work.

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