dhis2-devs team mailing list archive

[Adebusoye Anifalaje <busoye@xxxxxxxx>]

Hi all,

To introduce a variation on this theme of generating min-max values: I expected that if you set data element number type to Zero of Positive Integer this should alter the distribution (in this case skew to the right as Jason put it) and avoid the negative minimum values. From the tests I have done, this is not happening. 

The negative mim values are a real pain, anyone with a solution yet?

Regards,

Busoye   

On 31 May 2013, at 14:53, Gulam Khan <gm-khan@xxxxxxxxxxxxxxxxxxxx> wrote:

> Hi Dapo,
> If you were to generate the min-max values automatically, insert them into the database, and an authorized user was to change them, then they would be overwritten. 
> 
> You can automatically generate these values through the data administration module by dataset and orgunit in Data Administration->Min-Max Value Generation . The problem is you often end up with a lot of dubious values, such as negative numbers. This is a result of the Gaussian distribution model which is applied (without taking any skewness into effect). I have attached a plot from a real DHIS2 database, which show sthat the distribution of many in DHIS2 are skewed left or right (more often to the right) . Use of an unbounded, normal distribution for calculation of the min-max is therefore not really appropriate. The standard deviation approach is also highly sensitive to outliers, which also creates problems for the outlier analysis if this approach is used. Anyway, I digress. Just wanted to highlight that the in-built functions for calculation of the min-max are rather primitive, and may not always lead to good results. 
> 
> I am not so sure about the ability to restrict the time periods for which the mix-max is generated. I think you would end up with far too few data points to make a meaningful standard deviation. You are really looking for the extremes with the min-max, and restricting to such a a narrow time interval would probably not give you these extremes. 
> 
> Regards,
> Jason
> 
> 
> 
> On Thu, Sep 19, 2013 at 11:47 PM, Dapo Adejumo <dapo_adejumo@xxxxxxxxx> wrote:
> Hi,
> 
> It will be great if the generation of min-max values can be automated based on a global setting ( ability to select last 3,6 or 12 months data) . I am curious what happens to these “hard coded” min/max values when the database is set to generate min/max values from the frontend – I will assume they are discarded since they reside in the same table? Or which takes precedence ?
> 
> Thanks.
> 
>  
> 
> ................................................
> 
>  
> 
> Regards,
> 
>  
> 
> Dapo Adejumo
> 
> +234803363677
> 
> skype : dapojorge
> 
>  
> 
> From: Dhis2-devs [mailto:dhis2-devs-bounces+dapo_adejumo=yahoo.com@xxxxxxxxxxxxxxxxxxx] On Behalf Of Jason Pickering
> Sent: Thursday, September 19, 2013 6:28 PM
> To: Juma Lungo
> Cc: dhis2-devs
> 
> 
> Subject: Re: [Dhis2-devs] Setting MinMax Values
> 
>  
> 
> I think I agree with Lars as well. Our use case was we wanted to restrict values between 0 and 31, and not do it with a validation rule, to provide visual clues during data entry. 
> 
>  
> 
> As an aside, one may also want to calculate these values and save them to the database. The current algorithm uses a standard deviation approach, which is problematic, in that in many cases the data which is typically observed does not follow a normal Gaussian distribution. Other statistical models often provide better estimates of the mix/max, but currently, cannot be calculated automatically by the system. If these values are calculated externally in some statistical package, they can be inserted back into the system (or even automated). 
> 
>  
> 
> Regards,
> 
> Jason
> 
>  
> 
>  
> 
> On Thu, Sep 19, 2013 at 6:25 PM, Juma Lungo <jlungo@xxxxxxxxx> wrote:
> 
> I agree with Lars
> 
>  
> 
> Lungo
> 
>  
> 
> From: Lars Helge Øverland <larshelge@xxxxxxxxx>
> To: Jason Pickering <jason.p.pickering@xxxxxxxxx> 
> Cc: dhis2-devs <dhis2-devs@xxxxxxxxxxxxxxxxxxx> 
> Sent: Thursday, September 19, 2013 2:43 PM
> Subject: Re: [Dhis2-devs] Setting MinMax Values
> 
>  
> 
> Hi Conrad,
> 
>  
> 
> the min-max data element is per org unit and data element like you say, so it applies to all current and future periods by definition. I don't know your use-case... but in general one might want to think twice before setting the same max value for all facilities, since they usually have very different catchment population and hence natural variations in numbers.
> 
>  
> 
> Lars
> 
>  
> 
>  
> 
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