Clinical Trial Participant Allocation Task
A Clinical Trial Participant Allocation Task is a Clinical Trial Management System that be solved by a Clinical Trial Participant Allocation System.
- AKA: Patient-to-Treatment Group Allocation Task, Clinical Trial Arm Assignment Task.
- Context:
- Input: Clinical Trial Participant IDs.
- Output: Allocation Sequence.
- It can range from being a Randomized Clinical Trial Participant Allocation Task to being a Deterministic Clinical Trial Participant Allocation Task.
- …
- Example(s):
- Counter-Example(s):
- See: Clinical Trial Arm, Blinded Clinical Trial, Placebo-Controlled Clinical Trial, Parallel Clinical Trial, Crossover Clinical Trial, Factorial Clinical Trial, Adaptive Clinical Trial, Clinical Data Management System, Clinical Trial Protocol.
References
2022a
- (ClinicalTrials.gov, 2022) ⇒ https://clinicaltrials.gov/ct2/about-studies/glossary Retrieved:2022-01-20.
- QUOTE: Allocation: A method used to assign participants to an arm of a clinical study. The types of allocation are randomized allocation and nonrandomized.
2022b
- (Spirit, 2022) ⇒ https://www.spirit-statement.org/methods-assignment-of-interventions-for-controlled-trials-16-17/ Retrieved:2022-01-20.
- QUOTE: Method of generating the allocation sequence (e.g., computer-generated random numbers), and list of any factors for stratification. To reduce predictability of a random sequence, details of any planned restriction (e.g., blocking) should be provided in a separate document that is unavailable to those who enrol participants or assign interventions.
- Example
"Participants will be randomly assigned to either control or experimental group with a 1:1 allocation as per a computer generated randomisation schedule stratified by site and the baseline score of the Action Arm Research Test (ARAT; <= 21 versus >21) using permuted blocks of random sizes. The block sizes will not be disclosed, to ensure concealment.
- Explanation
Participants in a randomised trial should be assigned to study groups using a random (chance) process characterised by unpredictability of assignments. Randomisation decreases selection bias in allocation; helps to facilitate blinding/masking after allocation; and enables the use of probability theory to test whether any difference in outcome between intervention groups reflects chance.
Use of terms such as “randomisation” without further elaboration is not sufficient to describe the allocation process, as these terms have been used inappropriately to describe non-random, deterministic allocation methods such as alternation or allocation by date of birth. In general, these non-random allocation methods introduce selection bias and biased estimates of an intervention’s effect size, mainly due to the lack of allocation concealment (...). If non-random allocation is planned, then the specific method and rationale should be stated.
- Explanation
- Example
- QUOTE: Method of generating the allocation sequence (e.g., computer-generated random numbers), and list of any factors for stratification. To reduce predictability of a random sequence, details of any planned restriction (e.g., blocking) should be provided in a separate document that is unavailable to those who enrol participants or assign interventions.
2022c
- (PSU, 2022) ⇒ PennState Eberly College Of Science (2022). "Lesson 8: Treatment Allocation and Randomization". In: STAT 509 - Design and Analysis of Clinical Trials, Retrieved:2022-01-20.
- QUOTE: Treatment allocation in a clinical trial can be randomized or nonrandomized. Nonrandomized schemes, such as investigator-selected treatment assignments, are susceptible to large biases. Even nonrandomized schemes that are systematic, such as alternating treatments, are susceptible to discovery and could lead to bias. Obviously, to reduce biases, we prefer randomized schemes. Credibility requires that the allocation process be non-discoverable. The investigator should not know what the treatment will be assigned until the patient has been determined as eligible. Even using envelopes with the treatment assignment sealed inside is prone to discovery.
Randomized schemes for treatment allocation are preferable in most circumstances. When choosing an allocation scheme for a clinical trial, there are three technical considerations:
- QUOTE: Treatment allocation in a clinical trial can be randomized or nonrandomized. Nonrandomized schemes, such as investigator-selected treatment assignments, are susceptible to large biases. Even nonrandomized schemes that are systematic, such as alternating treatments, are susceptible to discovery and could lead to bias. Obviously, to reduce biases, we prefer randomized schemes. Credibility requires that the allocation process be non-discoverable. The investigator should not know what the treatment will be assigned until the patient has been determined as eligible. Even using envelopes with the treatment assignment sealed inside is prone to discovery.
- Randomization procedures provide the best opportunity for achieving these objectives.
2014
- (Kim & Shin, 2014) ⇒ Jeehyoung Kim, and Wonshik Shin (2014)."How to Do Random Allocation (Randomization)".In: Clinic in Orthopedic Surgery (CiOS), 6(1):103-109. DOI:10.4055/cios.2014.6.1.103.
- QUOTE: Randomized controlled trials (RCT) are known as the best method to prove causality in spite of various limitations. Random allocation is a technique that chooses individuals for treatment groups and control groups entirely by chance with no regard to the will of researchers or patients' condition and preference. This allows researchers to control all known and unknown factors that may affect results in treatment groups and control groups.
Allocation concealment is a technique used to prevent selection bias by concealing the allocation sequence from those assigning participants to intervention groups, until the moment of assignment. Allocation concealment prevents researchers from influencing which participants are assigned to a given intervention group. This process must be included in the experiment for the success of any RCT.
Blinding refers to keeping trial participants, health care providers, assessors or data collectors unaware of the assigned intervention, so that they will not be influenced by that knowledge. This process is conducted to minimize possible bias in implementation, dropouts, measurements, etc. Blinding is not always feasible for RCT but should be implemented if possible.
- QUOTE: Randomized controlled trials (RCT) are known as the best method to prove causality in spite of various limitations. Random allocation is a technique that chooses individuals for treatment groups and control groups entirely by chance with no regard to the will of researchers or patients' condition and preference. This allows researchers to control all known and unknown factors that may affect results in treatment groups and control groups.
1978
- (White & Freedman, 1978) ⇒ S. J. White, and L. S. Freedman (1978). "Allocation of Patients to Treatment Groups in a Controlled Clinical Study". In: British Journal of Cancer, 37(5), 849-857.
- QUOTE: In a controlled clinical study ("clinical trial") to compare 2 or more treatments for a disease, an objective method of allocating patients to treatment groups is needed. Various existing methods of allocation are described, including those which take account of patients' pre-treatment characteristics.