[eml-dev] Revisiting the <measurementScale> categories

[inigo]

Thanks David. I hear you about the sense of not being happy with the 
adoption - 

All im saying is, since we have deeper problems with attributes, why 
complicating us more with 5 cats not fully discernible by a considerable 
segment of EML adopters?

I know you've been in touch with Dawn.  The short answer is not a chance 
- What do you think?  The longer answer later. We'll talk about Geo Bon, 
Kristin briefed me about your position.

cheers, inigo

David Blankman wrote:
> Inigo,
>
> In addition to the points that Matt made about  measurementScale there are
> other measurements that don't fall into any of the categories such as
> degrees/angular measurements. Originally these concepts were developed by
> social scientists as a way of determing what kinds if statistical tests
> would be valid. For example, factor analysis is not supposed to be performed
> on ordinal data. In practice, however, factor analysis is routinely done on
> Likert scales which are ordinal.
>
> If i remember coreectly, none of us were really satisfied with the use if
> measurementScale, however, we needed something and it was a workable, though
> clearly not perfect solution.
>
> On another matter, I have been working with GEO-Bon and was talking to Dawn
> \field. She directed me to some work that was being considered to extend EML
> to deal with molecular data. Has that progressed?
>
> David
> On Fri, Sep 19, 2008 at 6:31 PM, inigo <isangil at lternet.edu> wrote:
>
>   
>> For the record too. The <measurementScale> categories -- nominal, ordinal,
>> ratio, interval and datetime -- are not the best solution to classify the
>> recorded measurables in a data table.  The categories are not exempt from
>> controversy, and the guidelines and attempts to explain the proper use and
>> dissection of variable types have not succeeded in different uses.
>>
>> Example.  a "date" has been documented sometimes as "datetime", but also as
>> a "nominal or ordinal" and event "interval or ratio" - wonderful spread.
>> these type of classification ambiguity is normal to certain extent, but
>> something can be done to improve both the efficiency of the data
>> documentation and post-processing and community agreement on practices.
>> a good number of LTER sites have in practice simplified these categories
>> further.  essentially, there are 'dates', 'quantifiable measurables' and
>> 'all the rest' ( all the rest includes free text such as comments,
>> identifiers, pair of code-code definitions, nominals and ordinals).  This
>> practice has been adopted to remove part of ambiguities that the original
>> categories present, and for clarity of use.  a few people may feel that the
>> differences between those categories is crystal clear - no doubt - but i
>> have not found many of those.
>> If exploring different categories (identifiers, codes, quantifiable
>> measure, text, flags, dates..) for EML is something that no eml-dev is even
>> willing to consider, perhaps reducing the number from 5 to 3 would be a
>> humbler goal for the sake of efficiency.  Sure, someone may be tempted to
>> divide an interval type by a ratio type with undesirable results as a
>> consequence, but i think the risk is still there now (because of the use in
>> practice).
>> cheers, inigo
>>
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>>     
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