Thanks everyone. It is good to understand how the max/min is calculated in DHIS (the documentation should be updated with the content of this email). We definitely need other ways to set min/ max values - my case has a specific logic, which needs to be implemented via SQL, until there is a way to push these values via the API.
Can I confirm that the Min/ Max are set by - Data Element - Org Unit - Cat Combo - Attribute Combo? 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 4:02 PM, Calle Hedberg <calle.hedb...@gmail.com> wrote: > Hi > > "Calle is right here - we do average, then calculate std dev and set the > upper and lower bounds for each value. We use data from ALL available > time periods to calculate this (period org unit, data element, option > combo)." > > Here and there and back again :-) > > So I wasn't off the reservation, then. We have used the normal > distribution like this in DHIS 1.x for around 17 years, and it fits the > majority of data elements. In general, this distribution model handles > random outbreaks and disruptions reasonably well, since the impact of such > outliers are dampened. Data elements representing conditions or services > with strong seasonal variation do not fit so well, and some very particular > issues like "Male condoms distributed" tend to vary so much that the > min/max is generally disregarded (outliers here also matter a lot less - > when you distribute 1-2 billion condoms annually, an error of a few > thousand does not matter). In DHIS 1.4 there is also a function for setting > absolute min-max values - most typically used for data elements where e.g. > only 0 and 1 are valid values. For such cases, statistically calculating > min-max is obviously irrelevant. > > I don't like the use of ALL available time periods, though, since a large > number of health facilities will see significant changes in their patient > mix and patient numbers over let us say a 10 year period. We have found > that 12-18 months provide a good compromise. > > So there are still some room for improvement. > > Regards > Calle > > On 20 April 2015 at 16:15, Jason Pickering <jason.p.picker...@gmail.com> > wrote: > >> Good. I probably should have known that already, thus why I had to do >> some statistical analysis outside of DHIS2 to actually calculate reasonable >> min max. A quick check of the validity of a normal distribution, can be >> with the skewness and kurtosis , which provide a idea of how "tilted" a >> given distribution is. >> >> https://www.dhis2.org/doc/snapshot/en/developer/html/apas06.html >> >> Anyway, support for import via the API would be good. >> >> Regards, >> Jason >> >> On Mon, Apr 20, 2015, 16:06 Lars Helge Øverland <larshe...@gmail.com> >> wrote: >> >>> Hi there, >>> >>> Calle is right here - we do average, then calculate std dev and set the >>> upper and lower bounds for each value. >>> >>> We use data from ALL available time periods to calculate this (period >>> org unit, data element, option combo) >>> >>> Mind you we should not really debate whether to use standard deviations >>> or not, rather if we should support additional _distributions_ to better >>> handle different kinds of data. We currently use the normal distribution >>> <http://en.wikipedia.org/wiki/Normal_distribution>. >>> >>> Rodolfo - supporting min-max in the Web API is a good idea to allow for >>> third-party tools - feel free to write a blueprint. >>> >>> regards, >>> >>> Lars >>> >>> >>> >>> >>> >>> > > > -- > > ******************************************* > > 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-d...@lists.launchpad.net > Unsubscribe : https://launchpad.net/~dhis2-devs > More help : https://help.launchpad.net/ListHelp > >
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