Intention-to-treat

Intention-to-treat analysis (ITT) is a statistical method used in randomized controlled trials. It compares the treatment groups exactly as they were originally allocated. This means that the treatment group will include all patients regardless of whether they dropped out, fully adhered to the treatment, or crossed over and received the alternative treatment.

Overview

The intention-to-treat analysis is based on the initial treatment intent, not on the treatment eventually administered. ITT analysis is intended to avoid various misleading artifacts that can arise in intervention research such as non-random attrition of participants from the study or crossover.

Advantages

The main advantage of ITT analysis is that it respects the randomization process of the trial. Since randomization is the key to avoiding bias in clinical trials, this is a major strength of ITT analysis. It also reflects a pragmatic approach, recognizing that in practice patients do not always receive their intended treatment.

Disadvantages

The main disadvantage of ITT analysis is that it can underestimate the efficacy of a treatment, because it includes data from patients who have not adhered to the treatment. However, this is also a strength, because it provides information about the likely impact of the treatment in a real-world setting, where not all patients will adhere to treatment.

See also

• Per-protocol analysis
• As-treated analysis
• Clinical trial
• Randomized controlled trial

References

Intention-to-treat Resources
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