3.2. Data elements: The What dimension

3.2.1. Data element categories

The data element mentioned above ,"Measles doses given", can be further disaggregated into by combinations of data element categories. Each system administrator of DHIS2 is free to define any data element category dimensions for data elements. There are however, certain best practices which should generally be followed.

Given the example of Measles vaccination, if you want to know whether these vaccines were given at the facility (fixed) or out in the community as part of the outreach services then you could add a dimension called e.g. "Place of service" with the two possible options "Fixed" and "Outreach". Then all data collected on measles immunisation would have to be disaggregated along these to options. In addition to this you might be interested in knowing how many of these children who were under 1 year or above 1 year of age. If so you can add an Age dimension to the data element with the two possible options "<1 y" and ">1 y". This implies further detail on the data collection process. You can also apply both categories "Place of service" and "Age" and combine these into a data element category combination e.g. called "EPI disaggregation". You would then be able to look at four different more detailed values in stead of only one as in the example above for the data element "Measles doses given": 1) "Fixed and <1 y, 2) Fixed and >1 y, 3) Outreach and <1 y, and 4) Outreach and >1 y. This adds complexity to how data is collected by the health facilities, but at the same time opens up for new possibilities of detailed data analysis of Measles immunisation.

Table 3.2.  Example of detailed storage of data values when using data element categories "Place of Service" and "Age" (simplified for readability compared to the actual database table)

Organisation UnitData ElementPlace of serviceAgePeriodValue
Gerehun CHCMeasles doses givenFixed<1 yDec-0912
Gerehun CHCMeasles doses givenOutreach<1 yDec-094
Gerehun CHCMeasles doses givenFixed>1 yDec-094
Gerehun CHCMeasles doses givenOutreach>1 yDec-092
Tugbebu CHPMeasles doses givenFixed<1 yDec-0910
Tugbebu CHPMeasles doses givenOutreach<1 yDec-094
Tugbebu CHPMeasles doses givenFixed>1 yDec-093
Tugbebu CHPMeasles doses givenOutreach>1 yDec-091

3.2.2. Data element group sets

While the data element categories and their options described above provide the level of detail (disaggregation) at the point of data collection and how data values get stored in the database, the data element group sets and groups can be used to add more information to data elements after data collection. As an example, if you are analyzing many data elements at the same time in a report, you would want to group these based on some criteria. Instead of looking at all the data captured in a form for immunisation and nutrition, you might want to separate or group data elements along a programme dimension (known as a data element group set in DHIS2) where "Immunisation" (or EPI) and "Nutrition" would be the two groups.

Expanding the report to include data from other programs or larger themes of health data would mean more groups to such a group set dimension, like "Malaria", "Reproductive Health", "Stocks". For this example, you would create a data element group set called "Programme" (or whatever name you find appropriate), and to represent the different programmes in this dimension you would define data elements groups called "EPI", "Nutrition", "Malaria", "Reproductive health" and so on, and add all these groups to the "Programme" group set. To link or tag the data element "Measles doses given" to such a dimension you must (in our example) add it to the "EPI" group. Which groups you add "Measles doses given" to does not affect how health facilities collect the data, but adds more possibilities to your data analysis. So for the group set dimensions there are three levels; the group set (e.g. "Programme"), the group (e.g. "EPI"), and the data element (e.g. "Measles doses given").

Indicators can be grouped into indicator groups and further into indicator group sets (dimensions) in exactly the same way as data elements.

Table 3.3. 

Organisation UnitData ElementProgrammePeriodValue
Gerehun CHCMeasles doses givenEPIDec-0922
Gerehun CHCVitamin A givenNutritionDec-0916
Tugbebu CHPMeasles doses givenEPIDec-0918
Tugbebu CHPVitamin A givenNutritionDec-0912
Gerehun CHCMalaria new casesMalariaDec-0932
Tugbebu CHPMalaria new casesMalariaDec-0923