RD - Commission on Dietetic Registration (CDR) Practice Test

In research, which participant assignment strategy helps to eliminate bias in studies?

1. Stratified sampling

2. Random assignment

3. Matched pairing

4. Qualitative grouping

The correct answer is: Random assignment

Random assignment is a method used in research to allocate participants to different groups in a way that is entirely based on chance. This approach is crucial for eliminating bias, as it ensures that each participant has an equal opportunity to be assigned to any of the experimental or control groups. By doing so, random assignment helps to balance out any confounding variables – characteristics that may influence the outcome of the study but are not the primary focus of the research. This balance is achieved on average across a large sample size, allowing researchers to make more reliable conclusions about the effects of the treatment or intervention being studied. In contrast, other methods like stratified sampling, matched pairing, and qualitative grouping have specific advantages but do not inherently eliminate bias in the same way. Stratified sampling involves segmenting the population into subgroups and sampling from each, which can lead to selection bias in certain contexts. Matched pairing focuses on pairing participants based on certain characteristics, which may inadvertently introduce bias if those characteristics are linked to the outcome. Qualitative grouping is less structured and often lacks the statistical rigor needed to mitigate bias effectively. Therefore, random assignment stands out as the most effective strategy for ensuring unbiased participant assignment in research studies.