dhis2-devs team mailing list archive

[Abyot Gizaw <abyota@xxxxxxxxx>]

On Thu, Oct 1, 2009 at 9:28 AM, Jason Pickering <jason.p.pickering@xxxxxxxxx
> wrote:

> >> It is still not clear to me how the
> >> multidimensional data elements are used to calculate indicators in the
> >> same was as PODE (plain ol,d data element).  I guess this is handled
> >> somehow by the API?
>
> >> I have not played around with this, but I suppose it is possible
> >> somehow from wihtin the  indicator definition panels.
>
> Well, I have now played around with it and see more or less how it
> works. I have promised Lars I would try and put together some more
> documentation on the multidimensional data elements funcitonality,
> which I will try and distill together out of all these mails. But
> first a few more questions.
>
> Once I define an data element (Clinical Malaria) with Cateogries (Age
> (3 cateogory options) /Gender (2 cateogory options)) I get six data
> elements in my entry screen corresponding to the combination of all of
> these. When I go to define an indicator (say Malaria incidence for
> under 1), I can select these "sub-elements" . So for the numerator I
> get something like
>
> Clinical Malaria (Under1, Female,) + Clinical Malaria (Under1, Male,)
>
> and for the denominator, I would choose a semi-permanent data element
> like population..
>
> Age Under 1
>
> That is pretty sweet and I can calculate a Clinical Malaria under 1
> incidence rate, so defining inidcators with multidimensional data
> elements seems to work fine (have not tried to calculate anything but
> I guess this works as well).
>
> Anyway, my first question is about that last little comma. It would
> seem somehow (I have not looIked at the code) that there are
> three-dimensions that are sort of hard-wired. I have only defined two.
> Is that last comma significant, or just a bit of screen lint?
>

Yes that is just a bug! The for-loop adds a comma after each
"dimensionelement" assuming there will another one coming :-) we will tell
the loop not to add a comma if the "dimensionelement" is the last one (or
simply truncate in the end)


>
> Now, my next question which is a bit more erudite. Supposing I would
> go down the route of defining all of my indicators in a
> multidimensional fashion, is there any limit to the level of
> dimensionality that I can assign them and where should I start? Lets
> think about the malaria data element
>
> For malaria I might decide to get very complicated and choose many
> categories and options (Cateogories are after the number, possile
> cateogry options are in parentheses.
>
> 1) Type (Disease, Service delivery, equipment)
> 2) Disease type (Communicable, Non-communicable)
> 3) Transmission method (Vector Borne, Water borne, Air borne, Sexually
> transmitted)
> 4) Disease (Malaria, Leprosy, Leishmaniasis, etc)
> 5) Diagnosis status (Clinical, confirmed)
> 5) Patient status (OPD, IP, Deaths)
> 6) Age (Under 1, 1-5, Over 5)
> 7) Gender (Male, Female)
>
> This list is not complete, and would need some more category elements
> to be totally complete, but this enough to get started. So, I can see
> that if I define my categories and options like this, I will get a
> data element for "OPD Clinical Cases of Malaria Under 1" at some
> point.
>
> So, I guess my question is, where do i start to define my data element
> dimensionality? With Disease? There are dimensions "above" the disease
> however like I indicate here, like the transmission method. What if I
> want to be able to know the total number of cases of all vector borne
> diseases? Not a totally unusual request. Would I need to start the
> definition of my data elements from there? Would this need to be a
> "Dataelement group" instead? What about if I need to know the total
> number of cases of communicable diseases? Would this not imply I would
> need to add this data element to two seperate data element groups,
> which at least with DHIS 1.4 is a no-no as it results in duplicates in
> the PivotTables?
>
> It seems like we have stumbled on a partical accelerator. The deeper
> you dig, the more dimensions there are.
>

Emm...... I don't know. But I think there is a sort of bias here. Like
starting from a flat DHIS 1.4 dataelements and trying to genereate DHIS 2
dataelements by breaking into pieces. If I am not mistaken "OPD Clinical
Cases of Malaria Under 1"  is a common dataelement in 1.4 so you can start
to break this into pieces and get

"Under 1"
"Malaria"
"Clinical Cases"
"OPD"
....
...

but in the end getting confused which one is the dataelement which one is
the dimension. Well the MD model can handle such a breakup I guess but the
point is not that.

The point is, what users should do is I guess to first define what they need
from that functionality - what kind of data are they going to collect? what
does their dataentry screen look like?

The multimdimensionality model came into existence because of tabular
dataentry screens. As Ola suggested last time, there might a limitation with
this (multidimensionality - input screen) ... specifically when trying to do
some kind of analysis (like the Piovting thing mentioned). But how different
is the analysis going to be from our input formats? The way I see it, if
there is a need for further breakup during anaylsis then we have made a
mistake in defining our pieces during data collection. In most cases our
analysis is going to a combination and rearrangement of different pieces
collected by using our input screens.

Anyways for me a dimension is just an attribute to a dataelement. So before
talking about a dimension first we need to have a dataelement and
(logically) we can't mix the two!

Thank you
Abyot.


>
> Any practical suggestions. I know this is yet another erutdite
> example, but it highlights that if we are going to have
> multidimensional data elements, we need to be able to provide guidance
> on how they should be setup.
>
> Best regards,
> Jason
>
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