I'm currently evaluating a form design that uses Likert scales questions but it is possible that the user hasn't interacted with the product yet and may not know enough to answer the questions. The current form sets Don't Know/NA as the 0 score on the left end, 1 is equal to Not At All Important and 7 is Very Important, at the right end.
From my research, it looks like the best answer is to separate the Don't Know/NA response and place it to the side of the scale. Is that the best option for handling Don't Know/NA? Does anyone have examples of how they have handled this issue?