Composite locators include properties that individual locators do not, and understanding these properties can help you optimize your geocoding experience. Knowing when to modify properties on the individual participating locators and when to modify properties on the composite locator can help to get the best geocoding results and performance.
Spatial reference
When a composite locator is created, the spatial reference of the first participating locator is used as the spatial reference of the composite locator. When you convert a table to locations on the map, the output feature class is saved with the same spatial reference of the locator by default.
To modify the output
spatial reference, click the Select coordinate system button 
on the About the locator tab of the pop-up, and specify a spatial reference in the Coordinate system pop-up window.
Participating locators
The Participating locators tab displays a list of the individual locators that participate in a composite locator built with the Create Composite Address Locator tool and the properties and options of the participating locators that can be viewed or changed. This includes enabling and disabling participating locators, adding locators, and removing locators from the composite locator.
Note:
The maximum number of participating locators in a composite locator is 30, but it is recommended that you use no more than 10; otherwise, geocoding can be significantly slower.
Result order
When you create a composite locator, the order the locators are added to the Create Composite Address Locator tool determines the fallback order of the participating locators to which addresses can be matched against to increase the probability of finding the best match when geocoding. After the composite locator is created, you can adjust the geocoding fallback order of the participating locators to suit your needs. For example, you may have an ArcGIS StreetMap Premium multirole USA locator as well as your own custom locator for fire hydrants. If you create a composite locator with the USA locator and the hydrants locator, the default fallback order is to geocode using all roles of the multirole locator first; then use the custom locator. This order may not be optimal for your use case, and the order can now be adjusted using one of the following Result order options. Select one of the options to determine the fallback order used by the composite locator:
- Use locator order—Participating locators are in the order they were added to the Create Composite Address Locator tool and adhere to the fallback order described in Combine multiple locators into a composite locator.
- Order by role and score—Participating locators are grouped by role and fallback order. It is recommended that you use this option if you have a multirole
locator and several single role locators. This automatically orders your locators and
roles into a recommended, optimal fallback order.
- Custom order—A customizable fallback order for participating locators allows you to insert locators between the roles of a multirole locator. Locators cannot be inserted between multirole geocode services.
Note:
- The result order must be set prior to publishing the locator and must be republished to adjust the order after it has been published.
- Multirole ArcGIS StreetMap Premium locators display all locator roles, but support of these roles depends on the data and country. For example, the United States may not have data for sectors or districts.