TFS uses data warehouse and SQL Server Analytics server to drive reporting. As a result, we need to ensure that all of the fields we want to report on are included into TFS Warehouse database. We can set fields that we want to use for reporting within work item by using work item type definition language.

There are three effects that we can achieve while setting those fields to be reportable.

1. Data from the fields marked as reportable will be captured and stored into the data warehouse and later on included into reports.
2. Data from the field that is not marked as reportable will not get into data warehouse and will not be included into reporting.
3. If field is not marked as reportable, it will retain its original setting.
4. Field that is marked as reportable cannot be modified at the later time.

Reportable attribute takes three distinctive values: detail, measure and dimension.

1. Details attribute can be used only for integer, double, string or date time fields. Data from this field is stored into TFS Warehouse inside following tables: “Work Item History” and “Current Work Item” only.
   Example: <FIELD refname="MyCompany.MyField" name="MyField" type="String" reportable="detail">
2. Measure attribute can be used only for integer and double fields. It is set on the fields that we use for statistical purpose or when we measure certain aspects of the project.
   Example: <FIELD refname="MyCompany.MyField" name="MyField" type="Double" reportable="measure">
3. Dimension can only be set for integer, double, string or date time fields. Data stored in the TFS Warehouse as well as the cube. Dimension values are often used in the drop downs and such fields as State and Type are good candidates for the dimension attribute.
   Example: <FIELD refname="MyCompany.MyField" name="MyField" type="Double" reportable="dimension">