Pseudorandomisation

Pseudorandomisation is a method of assigning participants to treatment groups in a clinical trial or experiment. Unlike true randomisation, which relies on a truly unpredictable process, pseudorandomisation uses a deterministic algorithm to generate a sequence of assignments. This sequence may appear random to an observer but is in fact reproducible if the algorithm and its starting point are known.

Common methods for pseudorandomisation include using a table of random numbers generated by a computer program or a mathematical formula. The goal is to achieve a balance between treatment groups that closely resembles true randomisation, ensuring that confounding variables are distributed as evenly as possible.

While pseudorandomisation can be effective in practice and is often easier to implement than true randomisation, it carries a risk of predictability. If the algorithm or its seed is compromised, the allocation sequence could be predicted, potentially leading to bias. Therefore, robust methods for generating and storing the pseudorandom sequence are crucial for maintaining the integrity of the study. Despite this risk, pseudorandomisation is widely used and accepted in research settings when true randomisation is impractical or difficult to achieve.