dhis2-devs team mailing list archive

[Jason Pickering <jason.p.pickering@xxxxxxxxx>]

Sure, and that is my point that generation of min/max is not something
"Normal users" would do. This is a potentially complex operation, which
requires statistical knowledge.

But again, your insistence that it is calculated according to a "normal
model", I think it simply not right. It may work, but it might be worth to
confirm whether it is a valid assumption with you data before writing a
blueprint!

Regards,
Jason


On Mon, Apr 20, 2015 at 3:48 PM Calle Hedberg <calle.hedberg@xxxxxxxxx>
wrote:

> Hi,
>
> No generic model will fit ALL types of data elements, obviously - but it
> needs to fit the most typical data elements where you want to USE the
> min-max to capture e.g. reporting or capturing mistakes. If using a stdev
> model, you reset any negative values (which is impossible) to zero.
>
> Using the historic min and max in general makes the min-max useless for
> such pattern recognition, because any outbreak or campaign or disruption in
> a service for whatever reason will permanently affect the min/max so that
> they no longer represent the "normal" variation of a data element.
>
> But it seems I was wrong about this being implemented in DHIS2, then.
> Jason's comment that "in the past, we have pulled the data values into
> statistical software, calculated the min/max according to a given model,
> and then injected them back via SQL" clearly indicates what is required. We
> can argue over the model or models to be used, but some kind of model
> depicting normal distribution of values over time is clearly required. you
> cannot expect average users to be able to pull data values into STATA or
> SAS or SPSS, calculate min/max usign a given model, and then re-insert the
> values using SQL.
>
> I'll write a blue-print for this - either as part of the core or as an app
> - when I get my head above the water :-)
>
> Regards
> Calle
>
> On 20 April 2015 at 15:26, Jason Pickering <jason.p.pickering@xxxxxxxxx>
> wrote:
>
>> I think that would work, but as far as I know you cannot import these via
>> the API, but it is pretty trivial do it directly into the database.
>>
>> You might be able to script it however by calling to something like
>>
>>
>> https://apps.dhis2.org/demo/dhis-web-dataentry/saveMinMaxLimits.action?organisationUnitId=ImspTQPwCqd&dataElementId=BOSZApCrBni&categoryOptionComboId=TkDhg29x18A&minLimit=10&maxLimit=20
>>
>> Maybe the devs can suggest a better way, but in the past, we have pulled
>> the data values into statistical software, calculated the min/max according
>> to a given model, and then injected them back via SQL.
>>
>> Regards,
>> Jason
>>
>>
>> On Mon, Apr 20, 2015 at 3:22 PM Rodolfo Melia <rmelia@xxxxxxxxxxxx>
>> wrote:
>>
>>> my test also shows that only the min/max across all values of an org
>>> unit is use for setting mix/max. As this is unlikely to change any soon, I
>>> just want to understand if I can set the min/max values based on my own
>>> logic, and then inject it via the API.
>>>
>>> *Rodolfo Meliá*
>>> *Principal  |  *rmelia@xxxxxxxxxxxx
>>> Skype: rod.melia  |  +44 777 576 4090  |  +1 708 872 7636
>>> www.knowming.com
>>>
>>> On Mon, Apr 20, 2015 at 2:14 PM, Jason Pickering <
>>> jason.p.pickering@xxxxxxxxx> wrote:
>>>
>>>> HI,
>>>>
>>>> I think as Prosper says, it is simply the overall max and min, and this
>>>> can be set by the user, or calculated externally.
>>>>
>>>> Calle, use of standard deviation is problematic for several reasons
>>>> however, mostly because it makes an assumption that the data is actually
>>>> normally distributed, which is not really always the case. This may be
>>>> appropriate for some data elements, but in many cases, it is not an
>>>> appropriate statistical assumption, and results which we have seen after
>>>> often zero inflated or follow something more like a logistical distribution
>>>> (as opposed to a normal distribution).  So applying something like  a
>>>> standard deviation may (and does in the case of DHIS2)  result in many
>>>> negative min values. So, although I think the method of DHIS 1.4 may be
>>>> somewhat better, it still is not really always appropriate, as the
>>>> assumption of a normal distribution is simply not always warranted.
>>>>
>>>> Regards,
>>>> Jason
>>>>
>>>>
>>>>
>>>> On Mon, Apr 20, 2015 at 3:02 PM Calle Hedberg <calle.hedberg@xxxxxxxxx>
>>>> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> Sorry, but if the automatic min-max calculation is simply retrieving
>>>>> the historical minimum and maximum values, then that makes little sense and
>>>>> would have no real value.
>>>>>
>>>>> I don't have time to verify it right now, but my assumption has always
>>>>> been that DHIS2 is using a method similar to the one in DHIS 1.4:
>>>>>
>>>>> 1.
>>>>> The user specify a period to be used for the min/max analysis -
>>>>> typically 12-18 months (longer is better in a stable health establishment
>>>>> environment, but a shorter period might be optimal in areas where patient
>>>>> numbers are changing rapidly)
>>>>>
>>>>> 2.
>>>>> The average and standard deviation is calculated for each
>>>>> OrganisationUnit and DataElement combination
>>>>>
>>>>> 3.
>>>>> The min is set to the average minus stdev x constant, max is set to
>>>>> average plus stdev x constant. Typically constants are 1.5 - 2.0  (There is
>>>>> an "Data analysis std dev factor" specified under General Settings -
>>>>> by default set to 2.0. System might be using that).
>>>>>
>>>>> Best regards
>>>>> Calle
>>>>>
>>>>>
>>>>> On 20 April 2015 at 14:49, Rodolfo Melia <rmelia@xxxxxxxxxxxx> wrote:
>>>>>
>>>>>> Thanks Prosper - that makes sense.
>>>>>> I guess that the only way to set a different rule (e.g., Max should
>>>>>> be 150% than previous period) the max will need to be set via an app.
>>>>>>
>>>>>> Are Max/ Min of a Data Element/ Org Unit exposed in the API ?
>>>>>>
>>>>>> R
>>>>>>
>>>>>> *Rodolfo Meliá*
>>>>>> *Principal  |  *rmelia@xxxxxxxxxxxx
>>>>>> Skype: rod.melia  |  +44 777 576 4090  |  +1 708 872 7636
>>>>>> www.knowming.com
>>>>>>
>>>>>> On Mon, Apr 20, 2015 at 1:29 PM, Prosper BT <ptb3000@xxxxxxxxx>
>>>>>> wrote:
>>>>>>
>>>>>>> Hi Rodolfo,
>>>>>>>
>>>>>>> Used its before and according to the results we got, it takes the
>>>>>>> ever max and min entered in the selected period for a given dataset.
>>>>>>>
>>>>>>> Regards
>>>>>>>
>>>>>>> On Mon, Apr 20, 2015 at 3:24 PM, Rodolfo Melia <rmelia@xxxxxxxxxxxx>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> I'm trying to understand how does DHIS generates the Min/ Max
>>>>>>>> values for a given Data Element/ Period. The documentation
>>>>>>>> <https://www.dhis2.org/doc/snapshot/en/user/html/ch12s03.html>
>>>>>>>> only makes reference to the fact that Max/Min can be set manually or
>>>>>>>> automatically calculated. When automatically calculated: does anyone knows
>>>>>>>> what is the logic used for setting the values? Twice the average of
>>>>>>>> previous periods?
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> Mailing list: https://launchpad.net/~dhis2-users
>>>>>>>> Post to     : dhis2-users@xxxxxxxxxxxxxxxxxxx
>>>>>>>> Unsubscribe : https://launchpad.net/~dhis2-users
>>>>>>>> More help   : https://help.launchpad.net/ListHelp
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Prosper Behumbiize, MPH
>>>>>>> Phone:        +256 414 320076
>>>>>>> Cell:             +256 772 139037
>>>>>>>                      +256 752 751776
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>>
>>>>> Mailing list: https://launchpad.net/~dhis2-devs
>>>>>> Post to     : dhis2-devs@xxxxxxxxxxxxxxxxxxx
>>>>>> Unsubscribe : https://launchpad.net/~dhis2-devs
>>>>>>
>>>>> More help   : https://help.launchpad.net/ListHelp
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>>
>>>>> *******************************************
>>>>>
>>>>> Calle Hedberg
>>>>>
>>>>> 46D Alma Road, 7700 Rosebank, SOUTH AFRICA
>>>>>
>>>>> Tel/fax (home): +27-21-685-6472
>>>>>
>>>>> Cell: +27-82-853-5352
>>>>>
>>>>> Iridium SatPhone: +8816-315-19274
>>>>>
>>>>> Email: calle.hedberg@xxxxxxxxx
>>>>>
>>>>> Skype: calle_hedberg
>>>>>
>>>>> *******************************************
>>>>>
>>>>>  _______________________________________________
>>>>> Mailing list: https://launchpad.net/~dhis2-devs
>>>>> Post to     : dhis2-devs@xxxxxxxxxxxxxxxxxxx
>>>>> Unsubscribe : https://launchpad.net/~dhis2-devs
>>>>> More help   : https://help.launchpad.net/ListHelp
>>>>>
>>>>
>>>
>
>
> --
>
> *******************************************
>
> Calle Hedberg
>
> 46D Alma Road, 7700 Rosebank, SOUTH AFRICA
>
> Tel/fax (home): +27-21-685-6472
>
> Cell: +27-82-853-5352
>
> Iridium SatPhone: +8816-315-19274
>
> Email: calle.hedberg@xxxxxxxxx
>
> Skype: calle_hedberg
>
> *******************************************
>
>