Table 2 Summary of alternative methods for calculating rank probabilities

Median survival

The greatest survival time when 50% patients are alive

No

Yes

Yes

Commonly used and clinically relevant; Easily summarized as statistic; May limit need for extrapolation;

Ignores what happens after 50% of subjects have experienced the event;

Expected survival

The greatest expected survival

No

Yes

Yes

Directly relevant for cost-effectiveness; Easily summarized as statistic;

Sensitive to tail of distribution (may involve extrapolation); Does not illustrate time-varying results or time of greatest treatment effect; May not be as clinically relevant;

Mean survival at time t

Greatest mean survival (area under the curve) up until time t

No

Yes

Yes

Limits need for extrapolation if time t corresponds to follow-up time of trial with shortest duration; Easily summarized as statistic

May be difficult to interpret; Requires subjective selection of time t; Ignores tails of distribution and does not illustrate time-varying results;

Hazard (ratio) over time

The smallest hazard (ratio versus reference treatment) over time

Yes

No

Yes for hazard,

Directly relates to model and may help emphasize changes in treatment effect over time;

Does not capture cumulative effect of treatment over time; May lead to over interpretation near tail of distribution; Cannot be summarized as statistic (requires graphical illustration); May be more difficult to understand;

No for hazard ratio

Survival proportion over time (Cumulative hazard over time)

The greatest survival (proportion) over time

Yes

Yes

Yes

Highly intuitive and clinically relevant; Can be easily compared to data;

Cannot be summarized as statistic (requires graphical illustration);

Mean survival over time

Greatest mean survival (area under the curve) over time

Yes

Yes

Yes

Reflects a cumulative summary of survival proportions up until that time point, thereby de-emphasizing tail of distribution;

Cannot be summarized as statistic (requires graphical illustration); May be more difficult to understand;