dhis2-devs team mailing list archive

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

Hi there. The current design is to take the mean, and calculate n-standard
deviations away from the mean, for a given data element/orgunit/catcombo
set of data values. If the data value is set to be zero or positive
integer, and can never have a negative value and does not follow a normal
distribution, then flooring the projected min/max at zero makes little
sense, if the distribution is not normal. Another distribution would be
required to determine what the accepted min/max actually are (logistical,
zero-inflated model, etc) if the actual distribution is not normal.

But per the bug report, the application does what it is supposed to do,
namely calculate the theoretical min/max based on a stastical routine,
which itself may not be valid without confirming that the distribution in
question actually is normal or not.

Regards,
Jason


On Fri, Sep 18, 2015 at 11:57 AM, Lars Helge Øverland <larshelge@xxxxxxxxx>
wrote:

> This is not a design flaw. It depends on the data element value type
> property. The default value type is "number", for which negative values
> are perfectly valid. One can set the value type to "Positive number", in
> this case the min-max values will never be less than zero.
>
> ** Changed in: dhis2
>        Status: Opinion => Invalid
>
> --
> You received this bug notification because you are a member of DHIS 2
> developers, which is subscribed to DHIS.
> https://bugs.launchpad.net/bugs/1065014
>
> Title:
>   Min/Max generation goes into negative
>
> Status in DHIS:
>   Invalid
>
> Bug description:
>   A very minor bug, but the min/max generation algorithm (which I assume
>   is some std. dev) sometimes leads the minimum to be a negative number.
>   Probably not an issue per se for data quality, as the alternative
>   would be to set it to 0 (unless there is a reason why you would enter
>   negative numbers), but the chart you get when you double-click a data
>   entry field is then skewed and does not look very sensible. In extreme
>   cases, with a few very high values and a few months with very low (as
>   when you have campaigns or hand-outs), the minimum can be down to
>   minus a lot.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/dhis2/+bug/1065014/+subscriptions
>
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-- 
Jason P. Pickering
email: jason.p.pickering@xxxxxxxxx
tel:+46764147049