Include only fields from the record source that are absolutely
necessary. Extra fields can decrease combo or list box performance.

- Index the first field that is displayed in the combo or list box.

- Index any other fields used for criteria (such as when a combo or list
box is based on a criteria query).

- In combo boxes, set the AutoExpand property to No if it is not needed.

- Create a default value for combo boxes. Combo boxes try to match
whatever is entered in them, so if there is no default value for the
combo box, the combo box tries to match a null value when it is first
opened. An example of a default value for a combo box is:

=[combobox].ItemData(0)

In the example above, [combobox] is the name of the combo box.

- Use unbound subforms to display data when there is a large number of
records.