[R] Smallest Space Analysis (SSA) in R

Michael Friendly |r|end|y @end|ng |rom yorku@c@
Sun Sep 23 16:22:58 CEST 2018

On 9/22/2018 6:49 AM, Andrew wrote:
> Hi Michael
> This looks like it could be really helpful in moving my project forwards 
> thank you.
> I remember many years ago using (proprietary) software from the 
> University of Liverpool which did a nice job of allowing regions to be 
> defined, and then for the space to be rotated to obtain visual 
> inspection of relative distance from different angles. I appreciate that 
> smacof will not do that, but as long as the analysis allows for the 
> graph to be plotted and analysed, that's what's important.

You need not rely on the plots provided directly by a given package.
Just roll your own using standard plotting libraries.
Here is just the first Google hit on "R MDS 3D plot"


which shows a rotating 3D plot, colored by a grouping variable.  Here is 


The vegan and ade4 packages also have a variety of plots and related 


> Thank you again, and to all of those who responded.
> Best wishes
> Andrew
> On 21/09/18 14:07, Michael Friendly wrote:
>> Smallest space analysis (SSA) is just the name given to software 
>> developed by Guttman & Lingoes around the time the various versions
>> of multidimensional scaling were being developed.  Call it Israeli MDS
>> or Falafel MDS if you prefer. The reason you encountered it in your
>> course is presumably that the instructor was trained in that.
>> There are several variants of MDS-like algorithms for embedding
>> points representing objects in a space, using data representing
>> similarities or distances among objects -- metric (cmdscale)
>> and non-metric (MASS::isoMDS), using only rank order information, and 
>> a variety of
>> measures of goodness-of-fit ("stress").  I don't recall the details
>> of the SSA programs, but that should matter little conceptually.
>> The smacof package offers the widest array of possibilities.
>> -Michael
>> On 9/19/2018 7:00 AM, Andrew wrote:
>>> Hi
>>> As part of my forensics psych course, we have been introduced to
>>> Guttman's smallest space analysis (SSA). I want to explore this approach
>>> using R, but despite finding some queries on the web about this same
>>> thing, have yet to find any answers. The MASS package doesn't seem to do
>>> the job, and the only thing I have been able to find is some proprietary
>>> software HUDAP  (Hebrew University Data Analysis Package) which may/ not
>>> be compatible with R (or GNU/Linux for that matter).
>>> Does anyone have information on how to do SSA using R?
>>> Many thanks
>>> Andrew
>>>     [[alternative HTML version deleted]]

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