Step 1 - Build a template.
The template should include Numeric, Slider or Multi Slider type of questions.
These type of questions have a special option Preferred value:
Tick Preferred value checkbox and then set the expected value - this will be the best matching answer you'd like to get from respondent:
Step 2. Run a talk using this template
Let both participants give their answers. None of them will see what the preferred value is until the talk is over.
Step 3. Analize the report
After the talk is over open Report step - Spider graph.
Mark the questions you need and the participants you want to compare.
Average - aver. between respondents' answers
Preferred - the value specified in template
Gap - difference between Average and Preferred