Calculated fields file

Calculated fields my be used when existing fields are not grouped, categorized, or combined in a manner that makes analysis possible.  For example, Many jurisdictions that we've worked with have a field for "number of injuries" and "number of fatalities", but no field called "injury severity".  In this case, it is impossible to create a chart of the severity of the crashes for this database.  It is also not possible to send this category listing to a GIS for analysis.

Calculated fields allow you to examine the values of other fields and create a new field on-the-fly that is based on the values of the other fields.  So, in this example, to create an "injury severity" field one would say "if the number of fatalities is greater than 0, then this is a fatal crash; otherwise, if the number of injuries is greater than 0, then this is an injury crash; otherwise this was merely a property damanage only crash".  A calculated field can do this.

Once created, calculated fields are available in filters, charts, schematics and cross tabs.  They are not yet available in accident lists.

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Creating a calculated field