See Video:Download Flash Player STOPP® – Why it Matters

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Version 1.1 of STOPP® is for designing clinical trials, especially trials with interim analyses. 

While STOPP® is intended to be used for all types of designs, its greatest strength is in the design of survival trials.  STOPP® is the most advanced software anywhere for designing survival trials, with or without interim analyses.

STOPP® does not rely on cumbersome simulation procedures.

Based on the Markov model (Lakatos 1988)

  • whose capabilities far exceed that of simulation-based methods;

  • provides results within fractions of a second

  • handles noncompliance in addition to loss to follow-up (beware of programs adjusting for “dropout”)

  • used by some of the most prestigious clinical trial statistical centers

  • used by some of the most prestigious clinical trial statisticians

  • used in some of the most important clinical trials

Includes the unique graph-reader interpreter module (patent pending) for estimating hazard functions from prior trials

STOPP® facilitates designer boundaries for optimal and adaptive designs.

Unique interfaces

  • clear intuitive interfaces

    •  designed by the statistician who introduced and enhanced these methods in over 20 years as a consultant in these types of trials

  •  two sets of interfaces for survival

    • one for the novice, also useful for the expert wanting a quick answer to a more routine design

    • one for experts investigating complex designs that affords unprecedented flexibility as well as for researchers exploring uncharted territory

Unique ability to store complex design configurations for future reference and manipulation as design parameters evolve.                 

STOPP® software was made possible by SBIR Grant Number R44CA101617 from the National Cancer Institute of the National Institutes of Health.

order STOPP® online by visiting