---
title: "design_swss"
output: md_document
---

# Lower stopping boundaries

For a multi-stage group-sequential design, __multiarm__ requires a choice about the type of lower (futility) stopping boundary to use.
This can be either fixed (a common interim value), O'Brien Fleming, Pocock, or triangular.
Specify your chosen type of lower stopping boundary here.
If fixed is chosen, an input box will appear for you to specify the common fixed interim stopping boundary.
