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Conducting Rigorous Research Seminar Workbook

6 Seminar Five

This session is protected time to work on the planning of your experimental trial and for the write up of your trial protocol. Based on this weeks lecture content you should now be able to add information about the specific randomisation strategy you plan to use.

6.1 Control Groups

6.1.1 Purpose

  • Minimizes Bias: Blinding helps prevent conscious or unconscious biases that can influence the outcomes of the trial, such as the placebo effect or the Hawthorne effect.
  • Enhances Objectivity: By keeping participants, researchers, and sometimes even outcome assessors unaware of who is receiving the treatment and who is receiving a control (placebo or standard treatment), blinding ensures that judgments about the effectiveness and safety of the treatment are based solely on objective criteria.
  • Increases Reliability: Blinding reduces the likelihood of deliberate or unintentional manipulation of results, as both researchers and participants are unaware of which group they belong to, preventing them from influencing the study outcome.
  • Improves Statistical Validity: Blinding helps maintain the statistical validity of the trial by reducing the risk of systematic errors, which can distort the results and lead to incorrect conclusions.
  • Ethical Considerations: Blinding helps ensure ethical standards are met by minimizing the potential for harm or unfair treatment to participants and ensuring that everyone has an equal chance of receiving the treatment being studied.

6.1.2 Levels

  • Open Label (Unblinded):
    • In an open-label trial, both the participants and the investigators are aware of the treatment assignments. There is no concealment of which participants are receiving the experimental treatment and which are receiving the control or placebo. Single-Blind:
    • In a single-blind trial, either the participants or the investigators are unaware of the treatment assignments. Typically, participants are blinded while investigators know which participants are receiving which treatments. This setup aims to minimize bias in outcome reporting.
  • Double-Blind:
    • In a double-blind trial, both the participants and the investigators are unaware of the treatment assignments. This is considered the gold standard in clinical trials as it minimizes bias from both the participants’ and investigators’ perspectives.
  • Triple-Blind:
    • In addition to participants and investigators, a third party (such as outcome assessors or statisticians) remains unaware of the treatment assignments in a triple-blind trial. This level of blinding further ensures the objectivity and integrity of the trial results.

6.1.3 People

  • Participants: Blinding participants ensures that their expectations or beliefs about the treatment don’t influence their perception of the outcomes, such as reporting symptoms or improvements.
  • Investigators: Blinding investigators prevents conscious or unconscious biases in treatment administration, data collection, and interpretation of results.
  • Outcome Assessors: Those responsible for assessing outcomes, such as lab technicians or evaluators, can be blinded to prevent bias in measuring and interpreting results.
  • Statistician: Blinding statisticians helps to ensure that the statistical analysis remains unbiased and objective. It prevents the statistician from being influenced by knowledge of the treatment groups, thus preserving the integrity of the data analysis process.

6.2 Useful information

SPIRIT guidelines (Table 1):

Staffordshire University Experimental Trial Protocol Template