I am often the unblinded individual in an otherwise blinded clinical trial. And, as part of my unblinded role, I am often asked to provide summary statistics for results when the summary statistics may unblind results either directly or indirectly. As a simple example of direct unblinding, when not all subjects have finished the trial, providing the number of subjects contributing to a summary statistic can unblind. So, I have a question: How do you provide summary statistics without unblinding anyone?
My current favored method is to provide the median as the main measure of central tendency with the following rules:
- If all subjects have completed the study or cohort with that treatment, provide the actual median.
- If not all subjects have completed the study or cohort with that treatment (e.g. if n_missing have not completed), take the median of the data with n_missing removed from the top, take the median of the data with n_missing removed from the bottom to establish the range of possible median values, and then provide as the summary statistic a uniformly distributed random number between those bounds.
I know that other methods include removing the last X values where X is the maximum number of subjects who could receive the current treatment if everyone were randomized to it, and then calculate the summary statistic based on that subset of the data.
Do you have another preferred method? Do you have tools that help you generate these statistics?