I was wondering what the difference was between Cog and WordSurv recently.  Damien Daspit, creator of Cog, provided this explanation:

Cog and WordSurv

Cog focuses on automatic comparison and analysis of word lists. Cog does not maintain all of the survey metadata or support manual decisions like WordSurv.

Using Cog with WordSurv

When Cog is more fully developed and WordSurv is correspondingly updated, Cog and WordSurv would be used as together as complimentary software, interacting with import and export features. Here is a possible way:

• A surveyor would begin with WordSurv, entering all survey data and word lists.
• The word lists could then be imported into Cog for automatic comparison and analysis. Cog could be used to help the surveyor in understanding and analyzing the word lists quickly.
• Decisions made by Cog could be imported back into WordSurv if the surveyor is satisfied that it is sufficiently accurate.
• The decisions could made manually in WordSurv. The WordSurv database would be maintained as the primary data source. Even if the surveyor chooses not to keep the decisions made by Cog, it would still be useful in helping the surveyor to quickly learn about the data.