# Defining Summary Metrics in Insight

Summary metrics are defined in multiple places within Insight, such as charts, tables, and maps.  The method for defining these summaries is consistent and is explained below.

When first creating an Insight object such as a chart or table, the Summary Metrics list will be empty.

In most cases, by default, if you have not defined any metrics, the chart or table will compute counts.  To get started with more interesting metrics, click the Add Summary button.  This will open the Edit Summary Metric window, explained below.  If you have already created some metrics, you will see them in this summary metrics list, along with options for each.

The options available using the icon set  are, in order left to right:

## Edit Summary Metric Dialog

Clicking the Add Summary button or editing an existing metric will open this dialog.

• Variable  - Select the variable on which to base the summary metric calculation.
• Summary Function - Select the function used to compute the summary (see example below).  Most are self-explanatory, but others are explained here.  Not all summary functions are available for all variables.  For example, you will not be able to compute the average of a string variable.
• Count All- this summary function will return the total number of records in the filtered dataset.  The Variable selected above has no relevance if the Count All function is selected.
• Count Non Null - this function will count the valid, non-null values of the selected variable.
• Null Count - this summary function will return the total number of missing/null values for the selected Variable.
• Minimum and Maximum - these will return the minimum or maximum value of the Variable.  In the case of non-numeric fields, these functions will return the alphabetically ordered first and last values (respectively) of the selected Variable.
• Weighted Average - this summary function will return the average of the selected Variable, weighted by the Variable selected in the Weight Variable box.
• Correlation Coefficient - this summary function will return the standard Pearson correlation coefficient of the selected Variable, with the selected Weight variable.
• Weight Variable - If the Summary Function selected is Weighted Average or Correlation, the Weight Variable selection will be available.  A list of the numeric fields in the dataset are shown.  Select the variable to use as the weighting factor in computing the average, or the second variable to compute a correlation.
• Label - Enter the label to be given to the computed summary.  This should be unique relative to other summaries being computed.  If  you do not enter a name, an appropriate one will be created.  This label will be used in the chart, table, or other insight display.

Click this button to add a new summary based on a formula involving other summary metrics.

• Formula - In the formula field, enter a mathematical formula for the calculation.  When including the name of an already defined summary metric, enclose it in square brackets.  For example, the formula 100*[Response Rate] will turn a response rate into a percentage.
• Label - Provide a name for the new summary calculation.

When finished, click Save to save changes, or click Cancel to exit without saving work.