DHIS2 Category Combos at PSI
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Types of Category Combinations
DHIS2 Category Combos are the result of combining various DHIS2 Categories, like Sex and Age Groups, to create a new set of combinations.
For the example of Sex and Age Groups, if Sex has 2 values, and Age Group 4 values, we end up with 8 cat combos. For data entry, they will render as 8 columns.
Cat combos can also be used as an attribute on a Data Set or Program. It will render as one or more dropdown for the user to select before the data collection form loads.
Resulting Combinations
When creating Category Combos you need to ensure that the resulting number of combinations is a reasonable number. The table below explains the recommended limits. If you generate more that the recommended number of combinations, which can easily grow to the millions of combinations, will slow the system, make it unusable, and require a considerable level of effort for their removal.
 | CatCombo Rendering | Recommended maximum number of combinations |
|---|---|---|
 | How does the user sees it | estimate by multiplying the number of category options in each category |
As disaggregations | Renders as columns on a Dataset | Standard Dataset: no more than 15 |
As attribute | Renders as one or varios drop downs at the top of the dataset or program. User need to select a combination before the form loads | No more than 5,000. Example: = 20 x 75 = 1,500 cat combos. |
Creating and Maintaining Category Combos @ PSI - User Role/Authority
The assignment of the authority to create and maintain category combinations (private or public) is severely restricted at PSI due to the consequences that an inappropriate cat combo number of combinations can have in the overall health of the system. Users are given access to this authority after individual assessment of their DHIS2 knowledge and database/ system management experience. PSI’s DHIS2 server suffered of various cases of millions of cat combos being created, which made the server unusable for a couple of days, and required a significant clean up process.
Request for Creating and Maintaining Category Combos @ PSI
Please submit your request to create or modify a new cat combo via a ticket to the help desk.