Adaptive designs allow the use of data from an interim analysis to recalculate the sample size for the ongoing trial. The recalculation can follow various methods that differ in the conditional power arguments on which they are based. The simulation module in ADDPLAN includes the assessment of different sample size recalculation methods.
Simulations are available for

• one-sided and two-sided testing of means (paired and unpaired samples)
• one-sided and two-sided testing of proportions (paired and unpaired samples)
• noninferiority and equivalence (TOST) testing of means (difference and ratio specified)
• noninferiority and equivalence (TOST) testing of proportions (difference or relative risk specified)
• survival analysis
• non-inferiority and equivalence (TOST) for survival analysis.

Once a design is specified, the user can study the impact of

• the conditional power
• the bounds for the minimum and maximum sample size per stage
• the stopping for futility bound, overall or by stage, binding or non-binding, as required
• the choice of boundaries and planned information times
• the sample size allocation ratio, which can be changed from the default setting '1' to another value

on the performance of the trial in terms of power and ASN in case of testing of means or rates , or expected number of events/ expected duration in case of survival analysis, respectively.