Study DesignGlossary Term
A clinical trial in which participants are unaware of their treatment assignment, but the investigators and study personnel know which treatment each participant is receiving.
A single-blind study maintains concealment of treatment assignment from participants while allowing investigators and study staff to have full knowledge of the treatments being administered. This partial blinding protects against participant-related biases, such as differential reporting of symptoms based on treatment expectations, while accepting that investigator awareness may influence conduct and assessment of the trial. The approach represents a middle ground between open-label and double-blind designs.
Single-blind designs are selected when practical considerations prevent complete blinding but participant blinding remains achievable and valuable. In some studies, investigators must know the treatment assignment to provide appropriate medical care or to prepare treatments with different administration requirements. Certain treatments produce characteristic effects that would unblind investigators regardless of procedural efforts to maintain concealment. When participants can remain unaware of their treatment while investigator blinding is impractical, single-blind designs preserve some protection against bias.
The limitations of single-blind studies must be recognized and addressed through design and analysis choices. Investigator knowledge of treatment assignments can bias the conduct of examinations, the interpretation of results, and the recording of outcomes, particularly for endpoints requiring clinical judgment. To mitigate these risks, single-blind trials often employ standardized assessment procedures, blinded central readers for imaging or laboratory data, and independent endpoint adjudication committees. Outcome assessors who are distinct from the treating investigators can be blinded even when the treatment team is not, an approach sometimes called assessor blinding or evaluator blinding.
Infusion therapy trial
"The study was conducted single-blind because nurses needed to know which infusion each participant received to monitor for drug-specific reactions, but participants were not informed of their treatment assignment."
Physical therapy comparison
"The trial comparing two physical therapy approaches used a single-blind design in which participants were not told which therapy method they were receiving, though the treating therapists necessarily knew the assigned intervention."
The fraction of an administered dose of a drug that reaches the systemic circulation unchanged, and the rate at which this occurs.
A group of participants in a clinical trial who receive a comparator treatment, placebo, or no treatment to serve as a baseline for evaluating the effects of the investigational intervention.
A clinical trial design in which participants receive multiple treatments in sequence, with each participant serving as their own control by receiving all study treatments during different periods.
A systematic approach to increasing the dose of an investigational product during a clinical trial, typically employed in early-phase studies to identify safe and potentially effective dose levels.
A clinical trial in which both the participants and the investigators are unaware of the treatment assignments, providing maximal protection against bias in the conduct and assessment of the study.
A clinical trial in which participants are unaware of their treatment assignment, but the investigators and study personnel know which treatment each participant is receiving.
A single-blind study maintains concealment of treatment assignment from participants while allowing investigators and study staff to have full knowledge of the treatments being administered. This partial blinding protects against participant-related biases, such as differential reporting of symptoms based on treatment expectations, while accepting that investigator awareness may influence conduct and assessment of the trial. The approach represents a middle ground between open-label and double-blind designs.
Single-blind designs are selected when practical considerations prevent complete blinding but participant blinding remains achievable and valuable. In some studies, investigators must know the treatment assignment to provide appropriate medical care or to prepare treatments with different administration requirements. Certain treatments produce characteristic effects that would unblind investigators regardless of procedural efforts to maintain concealment. When participants can remain unaware of their treatment while investigator blinding is impractical, single-blind designs preserve some protection against bias.
The limitations of single-blind studies must be recognized and addressed through design and analysis choices. Investigator knowledge of treatment assignments can bias the conduct of examinations, the interpretation of results, and the recording of outcomes, particularly for endpoints requiring clinical judgment. To mitigate these risks, single-blind trials often employ standardized assessment procedures, blinded central readers for imaging or laboratory data, and independent endpoint adjudication committees. Outcome assessors who are distinct from the treating investigators can be blinded even when the treatment team is not, an approach sometimes called assessor blinding or evaluator blinding.
Infusion therapy trial
"The study was conducted single-blind because nurses needed to know which infusion each participant received to monitor for drug-specific reactions, but participants were not informed of their treatment assignment."
Physical therapy comparison
"The trial comparing two physical therapy approaches used a single-blind design in which participants were not told which therapy method they were receiving, though the treating therapists necessarily knew the assigned intervention."
The fraction of an administered dose of a drug that reaches the systemic circulation unchanged, and the rate at which this occurs.
A group of participants in a clinical trial who receive a comparator treatment, placebo, or no treatment to serve as a baseline for evaluating the effects of the investigational intervention.
A clinical trial design in which participants receive multiple treatments in sequence, with each participant serving as their own control by receiving all study treatments during different periods.
A systematic approach to increasing the dose of an investigational product during a clinical trial, typically employed in early-phase studies to identify safe and potentially effective dose levels.
A clinical trial in which both the participants and the investigators are unaware of the treatment assignments, providing maximal protection against bias in the conduct and assessment of the study.