**Formula indicators** are an excellent way to handle percentages or to view various types of aggregates. If you are interested in a metric such as "Percent of staff trained", the best way to manage this is to have two indicators for "Number of staff trained" and "Number of staff". DevResults can compute the percentage automatically. Computing percentages and certain totals can reduce data entry, reduce human error, provide a more thorough audit trail, and give more appropriate comparisions of percentages between places, time periods, and activities.

In the example below, we will compute

*% secondary students in rural schools*

To do so, we will need to divide

*# secondary students in rural schools*

by

*# students in secondary schools*

To reference these indicators in a formula, use the indicators' codes. You can find the indicator codes on the Indicator Definition page for the relevant indicators.

To define your indicator with a formula, click "From a Formula" as your Data Source option. In the box that appears, write the formula for the indicator. Use square brackets like [this] to reference an indicator by its code.

In this case, the code for:

# secondary students in rural schools is **2.5.7**

and the code for:

# students in secondary schools is **2.5.6**

When you click outside of the editing box, your formula will be saved. If the codes you referenced are incorrect, you will get an error message and will need to edit the formula. If the codes you referened are recognized by DevResults, then you will see a green checkmark and links to the indicators you've referenced.

**Codes for Disaggregations: **To denote an indicator's disaggregation, use a vertical bar "|" after the code within the bracket. For example, male students would be written as **[2.5.6|Male]**. You can also reference multiple disaggregations if your indicator is cross-disaggregated, such as **[2.5.6|Male|10th grade]**.

**Actual Values: **In the definition box, you can use numbers as well. For example, if you know that **# students in rural secondary schools** is consistently overcounted by 10%, you would create the formula **([2.5.7]*0.9)/[2.5.6]**.

**Multiple Indicators: **You can also use multiple indicators in a definition box. For example, **[****2.5.1] + [2.5.6] + [2.5.3]** might mean give the number of teachers plus students plus administrators.