15. The voice search system of claim 14 wherein the dialog component is configured to generate at least one of the features as a dialog feature indicative of a performance of the voice search system in responding to the spoken input.
15. The voice search system of claim 14 wherein the dialog component is configured to generate at least one of the features as a dialog feature indicative of a performance of the voice search system in responding to the spoken input. 16. The voice search system of claim 15 wherein the search system is configured to receive a keyboard text input as a second query and search the data store for a second search result based on the second query and wherein the confidence measure generator is further configured to generate a text search confidence measure corresponding to the second search result.