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.hedb...@gmail.com> 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 they no longer represent the "normal" variation of a data element.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.picker...@gmail.com> > 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 <rme...@knowming.com> >> 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 | *rme...@knowming.com >>> 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.picker...@gmail.com> 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.hedb...@gmail.com> >>>> 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 <rme...@knowming.com> 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 | *rme...@knowming.com >>>>>> 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 <ptb3...@gmail.com> >>>>>> 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 <rme...@knowming.com> >>>>>>> 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-us...@lists.launchpad.net >>>>>>>> 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@lists.launchpad.net >>>>>> 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.hedb...@gmail.com >>>>> >>>>> Skype: calle_hedberg >>>>> >>>>> ******************************************* >>>>> >>>>> _______________________________________________ >>>>> Mailing list: https://launchpad.net/~dhis2-devs >>>>> Post to : dhis2-devs@lists.launchpad.net >>>>> 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.hedb...@gmail.com > > Skype: calle_hedberg > > ******************************************* > >
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