dhis2-devs team mailing list archive

[Rodolfo Melia <rmelia@xxxxxxxxxxxx>]

Hi Lars - your example for population is correct. It makes sense. Our case
is scores calculated for quality assurance. On a given month we may get:
*Region A*
- Outlet 1: 90
- Outlet 2: 100
- Outlet 3: not conducted
- Outlet 4: 80

When looking in analytics at Region A, on the that month, we expect to get
90. We currently get 270, which is correct based on your explanation.

We will try to create an indicator that divides between 3 (so we need to
know conducted assessments). My worry is that the indicator will work of
that month, but when looking across multiple months, not sure about what
result will it return if we keep the aggregation = Avg.

R





*Rodolfo Meliá*
*Principal  |  *rmelia@xxxxxxxxxxxx
Skype: rod.melia  |  +44 777 576 4090  |  +1 708 872 7636
www.knowming.com


On Mon, May 19, 2014 at 2:36 PM, Lars Helge Øverland <larshelge@xxxxxxxxx>wrote:

> Hi Rodolfo,
>
> I am not sure if I understand you correctly so I will just try to explain
> how it works: With avg operator, you can get a valid "disaggregated" data
> value for period "within" the data collection frequency. So if you collect
> population with a yearly frequency for a data element with the avg
> operator, then you can also ask for the monthly value for a month in that
> year. In that case, the values will be the same - sort of a "standing
> value" for that period. If you have a value of e.g. 1000 people for the
> year, then the value for the month will also be 1000. This is just the
> nature of the data - if you have a population of 1000 for the year, then we
> must assume that the population for a month is also 1000.
>
> We do not allow "average within a period" or disaggregations for data
> element which naturally sums across time. As an example, if you collect
> cases of some disease at a quarterly frequency, we don't allow retrieving
> the value for a month within that quarter simply using the average. The
> reason is that it would not be valid statistics - we have no evidence that
> not all cases happened in the last month of the quarter, etc.
>
> regards,
>
> Lars
>
>
>
>
>
>
> On Mon, May 19, 2014 at 1:48 PM, Rodolfo Melia <rmelia@xxxxxxxxxxxx>wrote:
>
>> Hi Lars - thanks for the quick reply.
>>
>> I though AVG was valid within the same data-collection period as well as
>> across time. If this is the case, how do you calculate an average within
>> the same data collection period? AN indicator that divides the DE that has
>> the answer between valid answers? Normally that will be completed forms,
>> but such variable is not available as a denominator. We will have to use a
>> different Data Element that count valid answers. Last, such indicator will
>> make sense within the same period, but not across periods, as it will give
>> you an incorrect value, I think.
>>
>> Are you sure that AVG only makes sense across-time? Wouldn't be better to
>> also use the same logic within the same period? What's the rationale? If
>> there anyone out not wanting AVG to be calculated on the same data
>> collection period as across periods?
>>
>> R
>>
>> *Rodolfo Meliá*
>> *Principal  |  *rmelia@xxxxxxxxxxxx
>> Skype: rod.melia  |  +44 777 576 4090  |  +1 708 872 7636
>> www.knowming.com
>>
>>
>> On Mon, May 19, 2014 at 12:05 PM, Lars Helge Øverland <
>> larshelge@xxxxxxxxx> wrote:
>>
>>> Hi James,
>>>
>>> the "aggregation operator" refers to the time dimension - data will be
>>> averaged through time but still summed in the org unit hierarchy dimension.
>>> We could make this clearer in the system I guess.
>>>
>>> regards,
>>>
>>> Lars
>>>
>>>
>>>
>>> On Mon, May 19, 2014 at 12:55 PM, James Chang <jamesbchang@xxxxxxxxx>wrote:
>>>
>>>> Hi,
>>>>
>>>> On DHIS demo site, http://apps.dhis2.org/demo,
>>>> 'Average' aggregation operator seem to do 'Sum' instead.
>>>>
>>>> I didn't do any data entry or ran Analytics, but only looking at the
>>>> current data, 'Total Population' in 'Ngelehun CHC' and 'Njandama MCHP' seem
>>>> to sum on 'Badjia' even though the 'Total Population' is set to 'Average'
>>>> for Aggregation operator.
>>>>
>>>> See the attached images.
>>>>
>>>>
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>>>
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>>
>