# Missing Values

All data types accept a special value indicating that the data is "missing". For example, in a survey if a question wasn't answered the answer field should be marked as "missing". Missing data is typically ignored by charts.

You can manage the handling of missing values in two ways:

* **Show them:** Some charts allow missing values to be optionally included in the display. These views are: [Bar Chart](https://help.advizorsolutions.com/v7.2+/charts-and-visual-discovery/charts-overview/bar-chart), [Line Chart](https://help.advizorsolutions.com/v7.2+/charts-and-visual-discovery/charts-overview/line-chart), [Data Sheet](https://help.advizorsolutions.com/v7.2+/charts-and-visual-discovery/charts-overview/data-sheet), and [Histogram](https://help.advizorsolutions.com/v7.2+/charts-and-visual-discovery/charts-overview/histogram); see these descriptions for examples. Enabling inclusion of missing values using the "Show Missing Values" property in the [Property Explorer](https://help.advizorsolutions.com/v7.2+/using-advizor/author-ribbon/configure-charts/property-explorer). 
* **Label them:** For views that can display missing values, the string used may be specified. The default string is "\<NULL>". This may be specified in the **Tables** view in the [Project Workshop](https://help.advizorsolutions.com/v7.2+/using-advizor/author-ribbon/condition-data/project-workshop-view).&#x20;