
| State Variables   | Strategy Choices   |            |    |             |
|-------------------|--------------------|------------|----|-------------|
| U                 | I                  | P          | G  | AskUserName |
| SI Top MI Top     |                    |            |    |             |
| SI                | S                  | S SB SCP   |    |             |
| SI                | F RSO RCP          |            |    |             |
| R                 |                    |            |    |             |
| SI                | SI Top             |            |    |             |
| SI                | S                  | S S SB SCP |    |             |
| SI                | R                  | F RSO RCP  |    |             |
| SI                | SI Top             |            |    |             |
| SI                | S SB SCP           |            |    |             |
| S                 |                    |            |    |             |
| SI                | R                  | F RSO RCP  |    |             |
| MI                | S                  | S SB SCP   |    |             |
| MI                | F RSO RCP          |            |    |             |
| R                 |                    |            |    |             |
| MI                | MI Top             |            |    |             |
| MI                | S                  | S SB SCP   |    |             |
| MI                | F RSO RCP          |            |    |             |
| R                 |                    |            |    |             |
| MI                | MI Top             |            |    |             |
| MI                | S                  | S S SB SCP |    |             |
| MI                | R                  | F RSO RCP  |    |             |

for summarization varies according to the state of the task The different summarization The policy that is learned is to use the Summarize sstrategies were illustrated in Figure  
Both strategy at the beginning of the dialogue when TaskProg and then to switch to using the Summarize System strategy at later phases of the dialogue  This strategy makes sense in terms of giving the user complete information about all the messages in her inbox at the beginning of the dialogue

## Testing An Optimized Policy

We first constructed a deterministic version of ELVIS that implemented the learned policy as discussed above with one variation The variation was based on the fact that the decision on whether to use the Summarize Both or Summarize System summarization strategy was conditioned on the value of the TaskProg variable However we intended to utilize the op timized version of the system in situations where we would not have access to the TaskProg variable  namely situations where the task that the user was attempting to perform were not under the control of the experimenter   When we examined the values for the summariza tion strategies over the course of the dialogue we found that the Summarize System strategy had the greatest average value  being strongly preferred to the Summarize Both strategy except in the initial phase of the dialogue  where the    value for the Summarize Both was