**Local Control Phase Three:**

**EXPLORE**

In the third (but most important) phase of LC analysis, the outcomes researcher performs

Systematic Sensitivity Analyses!

Specifically, he/she explores the implications of using alternative ways to form clusters. For example, what sorts of LTD distributions result from (simultaneously) varying the following three LC analysis decisions?

[1] choice of number of clusters,

[2] choice of clustering algorithm / strategy, and

[3] choice of only a subset of the available patient X-characteristics.

This third phase can be quite **tedious **
and** ****repetitive** if the researcher has to specify each
alternative analysis to be performed. Ideally, software for
LC Analysis would minimize the need for user input when performing
sensitivity analyses ...via some form of “batch mode” processing.

The primary objective in
**Phase Three** is to identify, say, the three most
“interesting” LTD distributions that are typical (representative) of
all of the salient LTD distributions that have been identified in
sensitivity analyses. For example, which distribution is
typical of the salient distributions most favorable to a treatment?
Which distribution is most representative of the LTD
distributions least favorable to a treatment? And which LTD
distribution is most typical of all salient LTD distributions?

**Phase Four (REVEAL)**
analyses should concentrate upon these **most
typical LTD Distributions.**